Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U. S. National Acid Precipitation Assessment Program (NAPAP)

Energy Technology Data Exchange (ETDEWEB)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A. (US Geological Survey, Reston, VA (USA))

1992-06-01

Test briquettes and slabs of freshly quarried limestone and marble have been exposed to the environment to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulphur dioxide, and nitrogen oxides on stone erosion. Erosion due to grain loss did not seem to be influenced by rainfall acidity, but may be influenced by dry deposition of sulphur dioxide between rainfall events. Chemical analyses of the run-off solutions suggest that around 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulphur dioxide and nitric acid between rain events. The remaining 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in 'clean' rain. 17 refs., 4 figs., 7 tabs.

Deposition and conversion in soil of acids, acid-forming substances and nutrients

International Nuclear Information System (INIS)

Mayer, R.

1990-01-01

Balancing of material depositions entries is the basis for their evaluation. The acid depositions must be put in relation to the acid neutralization capacity and to the buffer rate of the soil. Every 'excess' in depositons leads to an acid supply into the sub-soil and/or into the groundwater system. On the one hand, the nutrient depositions are interpreted in relation to the nutrient supplies of the soil and their availability to the plants; and on the other hand with a view to the nutrient depletion through the polants. Excesses can also lead to a (non-desirable) pollution of aquatic systems, or else to an enhanced nutrient supply in the soil. Balancing is therefore a necessary aid for the evaluation of material depositions from the atmosphere. (orig./EF) [de

Soil Acidification due to Acid Deposition in Southern China

Energy Technology Data Exchange (ETDEWEB)

Liao, Bohan

1999-12-31

Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

Soil Acidification due to Acid Deposition in Southern China

Energy Technology Data Exchange (ETDEWEB)

Liao, Bohan

1998-12-31

Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

Acid deposition in the northern hemisphere

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Green, S.E.; Lee, D.S.

1987-02-01

Examines the phenomenon of acid deposition: the distribution and magnitude of sources and its actual and potential direct and indirect effects on soils, forests and other vegetation; wildlife, freshwaters, materials and health. The wide range of technological and other controls that are available to reduce the emissions of pollutants contributing to the phenomenon is also examined and includes pre-combustion control of pollutants, removal during combustion and post-combustion control. Also considered are political responses to acidification, acid deposition monitoring in the United Kingdom and the treatment of acidified areas.

Geological aspects of acid deposition

International Nuclear Information System (INIS)

Bricker, O.P.

1984-01-01

The general pattern of rain falling on the earth and reacting with the materials of the lithosphere (the weathering reactions so familiar to every beginning geology student) began soon after the earth was formed and has continued to the present. Anthropogenic additions to the natural acidic components of the atmosphere have increased since the time of the industrial revolution until they now rival or exceed those of the natural system. The severity of the environmental perturbations caused by these anthropogenic additions to the atmosphere has become a hotly debated topic in scientific forums and in the political arena. The six chapters in this book address various aspects of the acid deposition phenomenon from a geological perspective. It is hoped that the geological approach will be useful in bringing the problem more clearly into focus and may shed light on the geochemical processes that modify the chemical composition of acid deposition after it encounters and reacts with the materials of the lithosphere

Effects of deposition time in chemically deposited ZnS films in acidic solution

Energy Technology Data Exchange (ETDEWEB)

Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

2015-08-31

We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

Low-Vacuum Deposition of Glutamic Acid and Pyroglutamic Acid: A Facile Methodology for Depositing Organic Materials beyond Amino Acids.

Science.gov (United States)

Sugimoto, Iwao; Maeda, Shunsaku; Suda, Yoriko; Makihara, Kenji; Takahashi, Kazuhiko

2014-01-01

Thin layers of pyroglutamic acid (Pygl) have been deposited by thermal evaporation of the molten L-glutamic acid (L-Glu) through intramolecular lactamization. This deposition was carried out with the versatile handmade low-vacuum coater, which was simply composed of a soldering iron placed in a vacuum degassing resin chamber evacuated by an oil-free diaphragm pump. Molecular structural analyses have revealed that thin solid film evaporated from the molten L-Glu is mainly composed of L-Pygl due to intramolecular lactamization. The major component of the L-Pygl was in β-phase and the minor component was in γ-phase, which would have been generated from partial racemization to DL-Pygl. Electron microscopy revealed that the L-Glu-evaporated film generally consisted of the 20 nm particulates of Pygl, which contained a periodic pattern spacing of 0.2 nm intervals indicating the formation of the single-molecular interval of the crystallized molecular networks. The DL-Pygl-evaporated film was composed of the original DL-Pygl preserving its crystal structures. This methodology is promising for depositing a wide range of the evaporable organic materials beyond amino acids. The quartz crystal resonator coated with the L-Glu-evaporated film exhibited the pressure-sensing capability based on the adsorption-desorption of the surrounding gas at the film surface.

Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains

Science.gov (United States)

Nanus, L.; Williams, M.W.; Campbell, D.H.; Tonnessen, K.A.; Blett, T.; Clow, D.W.

2009-01-01

The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration 3000 m, with 80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

Microbial activity in an acid resin deposit: Biodegradation potential and ecotoxicology in an extremely acidic hydrocarbon contamination

International Nuclear Information System (INIS)

Kloos, Karin; Schloter, Michael; Meyer, Ortwin

2006-01-01

Acid resins are residues produced in a recycling process for used oils that was in use in the forties and fifties of the last century. The resin-like material is highly contaminated with mineral oil hydrocarbons, extremely acidic and co-contaminated with substituted and aromatic hydrocarbons, and heavy metals. To determine the potential for microbial biodegradation the acid resin deposit and its surroundings were screened for microbial activity by soil respiration measurements. No microbial activity was found in the core deposit. However, biodegradation of hydrocarbons was possible in zones with a lower degree of contamination surrounding the deposit. An extreme acidophilic microbial community was detected close to the core deposit. With a simple ecotoxicological approach it could be shown that the pure acid resin that formed the major part of the core deposit, was toxic to the indigenous microflora due to its extremely low pH of 0-1. - Acidity is the major toxic factor of the extremely hydrophobic and acidic mixed contamination found in an acid resin deposit

Acid deposition: sources, effects and controls

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S. (ed.)

1989-01-01

The purpose of this collection of 19 papers is to review our understanding of the cause and effect of acid deposition, to present new data that assist in the provision of a fuller understanding of cause, process and implication and thus to assist in defining the research agenda of the future. The materials presented are European in perspective, drawn from the Federal Republic of Germany, Hungary, Norway, Sweden and the United Kingdom. The current position as regards deposition monitoring, ecological effects and control technologies is presented in five sections: acid deposition monitoring, freshwater acidification, soils and forest systems, structural materials and control technologies. Each section is introduced by an overview paper outlining the contemporary understanding and identifying areas requiring future work. Specialist papers presenting new data or re-interpretations of existing information comprise the remainder of each section. Four of the papers have been abstracted separately.

Acid formic effect in zinc coatings obtained by galvanostatic deposition

International Nuclear Information System (INIS)

Lopes, C.; David, M.; Souza, E.C.

2016-01-01

Zinc deposits obtained from electrodeposition is widely used for the purpose of protecting steel substrates from corrosion. They are generally added to Zn deposition bath many additives for improving certain characteristics of the deposit. As far as is known there is no information in literature about the effect of formic acid in corrosion resistance of a Zn deposit. Because it is an acid additive, it has the use of cyclohexylamine, in order for the electrolytic bath continue with a pH equal to the one used commercially, around 5. The main goal of this study is analyze the effect of the formic acid addition in the corrosion resistance of an Zn electrodeposition obtained by galvanostatic deposition. The results obtained by performance tests, cyclic voltammetry and X-ray diffraction showed that the formic acid addition may be promising in combating the corrosion of materials. (author)

The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis

International Nuclear Information System (INIS)

Chapman, Pippa J.; Clark, Joanna M.; Reynolds, Brian; Adamson, John K.

2008-01-01

Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer. - Seasonal variations in soil solution ANC is controlled by seasonal variations in seasalt deposition and production of dissolved organic acids

Effects of acid deposition on ecosystems: Advances in the state of the science

Science.gov (United States)

Burns, Douglas A.; Fenn, Mark E.; Baron, Jill S.

2011-01-01

issues pertinent to ecosystem response to emission controls and acid deposition are receiving increasing attention in the scientific literature and will be discussed in this chapter, including the (1) observed delay in ecosystem recovery in the eastern United States, even with decreases in emissions and deposition over the past 30 years; (2) emerging ecosystem impacts of nitrogen deposition in the western United States; (3) the application of critical deposition loads as a tool for scientists to better inform air quality policies; (4) the role of changes in climate and the carbon cycle as factors that affect the response of ecosystems to acid deposition; and (5) the interaction of multiple pollutants in ecosystems. Throughout this chapter, the value of long-term environmental monitoring data in informing air quality policy will be highlighted, including the limitations of assessing the current status of some ecosystem indicators for which continuous, long-term data are lacking. 

Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

Energy Technology Data Exchange (ETDEWEB)

Deen, I. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Zhitomirsky, I., E-mail: zhitom@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

2014-02-15

Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties.

Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

International Nuclear Information System (INIS)

Deen, I.; Zhitomirsky, I.

2014-01-01

Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties

Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

Science.gov (United States)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A.

1992-01-01

One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30?? to horizontal at the five NAPAP materials exposure sites range from ~15 to ~30?? ??m yr-1 for marble, and from ~25 to ~45 ??m yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ~30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ~70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ('clean rain'). These results are for marble and limestone slabs exposed at an angle of 30?? from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60?? or 85??. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC

Acid deposition. Origins, impacts and abatement strategies

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S. (Manchester Polytechnic, Acid Rain Information Centre (United Kingdom). Dept. of Environmental and Geographical Studies) (ed.)

1991-01-01

The subject of acid deposition is one of the most important of our contemporary environmental problems. Presenting and discussing new data on the sources and effects of such deposition, this book seeks to assist in the definition of our future research requirements and policy developments. It is divided into four broad themes: Emissions, Chemistry and Deposition, Ecosystem Effects (freshwater, soils and forest systems), Effects on Structural Materials, and Mitigation, Control and Management. (orig.) With 130 figs.

Acid deposition study in the Asian countries

Energy Technology Data Exchange (ETDEWEB)

Soon, Ting-Kueh [Tunku Abdul Rahman College, Kuala Lumpur (Malaysia); Lau, Wai-Yoo [Malaysian Scientific Association, Kuala Lumpur (Malaysia)

1996-12-31

The Association of South East Asian Nations or ASEAN is a regional association of seven countries, namely Indonesia, Malaysia, Philippines, Singapore, Thailand, Brunei and Vietnam, located at the south eastern part of the Asian continent. Together with the East Asian States of Japan, China, Korea and Taiwan, this part of the world is experiencing rapid economic growth, especially in the last decade. Rapid industrialization has resulted in an increased demand for energy in the manufacturing and transport sectors, and also for infrastructure development. This has led to a significant increase in gaseous emissions and a corresponding increase in atmospheric acidity. Acid deposition study in the ASEAN countries began in the mid-70s when Malaysia first started her acid rain monitoring network in 1976. This was followed closely by Singapore and the other ASEAN countries in the 80s. By now all ASEAN countries have their own acid rain monitoring networks with a number of these countries extending the monitoring to dry deposition as well.

Effects of acidic deposition on forest and aquatic ecosystems in New York State

Energy Technology Data Exchange (ETDEWEB)

Driscoll, Charles T.; Driscoll, Kimberley M.; Mitchell, Myron J.; Raynal, Dudley J

2003-06-01

Elevated inputs of acidic deposition have deleterious effects on forest and aquatic ecosystems in New York. - Acidic deposition is comprised of sulfuric and nitric acids and ammonium derived from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia, respectively. Acidic deposition has altered soil through depletion of labile pools of nutrient cations (i.e. calcium, magnesium), accumulation of sulfur and nitrogen, and the mobilization of elevated concentrations of inorganic monomeric aluminum to soil solutions in acid-sensitive areas. Acidic deposition leaches essential calcium from needles of red spruce, making this species more susceptible to freezing injury. Mortality among sugar maples appears to result from deficiencies of nutrient cations, coupled with other stresses such as insect defoliation or drought. Acidic deposition has impaired surface water quality in the Adirondack and Catskill regions of New York by lowering pH levels, decreasing acid-neutralizing capacity, and increasing aluminum concentrations. Acidification has reduced the diversity and abundance of aquatic species in lakes and streams. There are also linkages between acidic deposition and fish mercury contamination and eutrophication of estuaries.

The nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Kurbonov, A.S.; Mamatov, E.D.; Suleymani, M.; Borudzherdi, A.; Mirsaidov, U.M.

2011-01-01

Present article is devoted to nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit of Tajikistan. The obtaining of boric acid from pre backed danburite concentrate by decomposition of nitric acid was studied. The chemical composition of danburite concentrate was determined. The laboratory study of danburite leaching by nitric acid was conducted. The influence of temperature, process duration, nitric acid concentration on nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit was studied as well. The optimal conditions of nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit, including temperature, process duration, nitric acid concentration and particle size were proposed.

Effects of acid deposition on microbial processes in natural waters

International Nuclear Information System (INIS)

Gilmour, C.C.

1992-01-01

Biogeochemical processes mediated by microorganisms are not adversely affected by the acidification of natural waters to the same extent as are the life cycles of higher organisms. Basic processes, e.g., primary production and organic matter decomposition, are not slowed in moderately acidified systems and do not generally decline above a pH of 5. More specifically, the individual components of the carbon, nitrogen, and sulfur cycles are, with few exceptions, also acid resistant. The influence of acid deposition on microbial processes is more often stimulation of nitrogen and sulfur cycling, often leading to alkalinity production, which mitigates the effect of strong acid deposition. Bacterial sulfate reduction and denitrification in sediments are two of the major processes that can be stimulated by sulfate and nitrate deposition, respectively, and result in ANC (acid-neutralizing capacity) generation. One of the negative effects of acid deposition is increased mobilization and bioaccumulation of some metals. Bacteria appear to play an important role, especially in mercury cycling, with acidification leading to increased bacterial methylation of mercury and subsequent bioaccumulation in higher organisms

Simulated dry deposition of nitric acid near forest edges

NARCIS (Netherlands)

DeJong, JJM; Klaassen, W; Jong, J.J.M. de

1997-01-01

Dry deposition is simulated to understand and generalize observations of enhanced deposition of air pollution near forest edges. Nitric acid is taken as an example as its deposition velocity is often assumed to be determined by turbulent transport only. The simulations are based on the

Acidic deposition along the Appalachian Trail corridor and its effects on acid-sensitive terrestrial and aquatic resources

Science.gov (United States)

Lawrence, Gregory B.; Sullivan, Timothy J.; Burns, Douglas A.; Bailey, Scott W.; Cosby, Bernard J.; Dovciak, Martin; Ewing, Holly A.; McDonnell, Todd C.; Minocha, Rakesh; Riemann, Rachel; Quant, Juliana; Rice, Karen C.; Siemion, Jason; Weathers, Kathleen C.

2015-01-01

The Appalachian National Scenic Trail (AT), a unit of the National Park Service (NPS), spans nearly 2,200 miles from Georgia to Maine, encompassing a diverse range of ecosystems. Acidic deposition (acid rain) threatens the AT’s natural resources. Acid rain is a result of sulfur (S) and nitrogen (N) compounds produced from fossil fuel combustion, motor vehicles, and agricultural practices. The AT is particularly vulnerable to S and N because it passes along ridgetops that receive higher levels of acid rain than lower valley terrain, and these ridges are often underlain by bedrock with minimal ability to buffer acidic inputs. Further, there are numerous S and N emission sources across the region. In the environment, acidic deposition can lower the pH of streams and soils which can ultimately affect fish, invertebrates, and vegetation that inhabit these areas. To address this concern, the MegaTransect Deposition Effects Study evaluated the condition and sensitivity of the AT corridor with respect to acidic deposition, and defined air pollution thresholds (critical and target loads) and recovery rates. Findings indicate that additional S emission

High frequency and large deposition of acid fog on high elevation forest.

Science.gov (United States)

Igawa, Manabu; Matsumura, Ko; Okochi, Hiroshi

2002-01-01

We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites.

Effects of acidic deposition on the erosion of carbonate stone — experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

Science.gov (United States)

Baedecker, Philip A.; Reddy, Michael M.; Reimann, Karl J.; Sciammarella, Cesar A.

One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30° to horizontal at the five NAPAP materials exposure sites range from ˜ 15 to ˜ 30 μm yr -1 for marble, and from ˜ 25 to ˜ 45 μm yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ˜ 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ˜ 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ("clean rain"). These results are for marble and limestone slabs exposed at an angle of 30° from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60° or 85°. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at

Expanding atmospheric acid deposition in China from the 1990s to the 2010s

Science.gov (United States)

Yu, Haili; Wang, Qiufeng

2017-04-01

Atmospheric acid deposition is considered a global environmental issue. China has been experiencing serious acid deposition, which is anticipated to be more serious with the country's economic development and increasing consumption of fossil fuels in recent decades. By collecting nationwide data on pH and concentrations of sulfate (SO42-) and nitrate (NO3-) in precipitation between 1980 and 2014 in China, we explored the spatiotemporal variations of precipitation acid deposition (bulk deposition) and their influencing factors. Our results showed that average precipitation pH values were 4.86 and 4.84 in the 1990s and 2010s, respectively. This suggests that precipitation acid deposition in China has not seriously changes. Average SO42- deposition declined from 30.73 to 28.61 kg S ha-1 yr-1 but average NO3- deposition increased from 4.02 to 6.79 kg N ha-1 yr-1. Specifically, the area of severe precipitation acid deposition in southern China has shrunk to some extent as a result of decreasing pollutant emissions, whereas the area of moderate precipitation acid deposition has expanded in northern China, associated with rapid industrial and transportation development. Significant positive correlations have been found between precipitation acid deposition, energy consumption, and rainfall. Our findings provide a comprehensive evaluation of the spatiotemporal dynamics of precipitation acid deposition in China over past three decades, and confirm the idea that strategies implemented to save energy and reduce pollutant emissions in China have been effective in alleviating precipitation acid deposition. These findings might be used to demonstrate how developing countries could achieve economic development and environmental protection through the implementation of advanced technologies to reduce pollutant emissions.

Acid deposition and water use efficiency in Appalachian forests

Science.gov (United States)

Malcomb, J.

2017-12-01

Multiple studies have reported increases in forest water use efficiency in recent decades, but the drivers of these trends remain uncertain. While acid deposition has profoundly altered the biogeochemistry of Appalachian forests in the past century, its impacts on forest water use efficiency have been largely overlooked. Plant ecophysiology literature suggests that plants up-regulate transpiration in response to soil nutrient limitation in order to maintain sufficient mass flow of nutrients. To test the impacts of acid deposition on forest eco-hydrology in central Appalachia, we integrated dendrochronological techniques, including tree ring δ13C analysis, with catchment water balance data from the Fernow Experimental Forest in West Virginia. Tree cores from four species were collected in Fernow Watershed 3, which has received experimental ammonium sulfate additions since 1989, and Watershed 7, an adjacent control catchment. Initial results suggest that acidification treatments have not significantly influenced tree productivity compared to a control watershed, but the effect varies by species, with tulip poplar showing greatest sensitivity to acidification. Climatic water balance, defined as the difference between growing season precipitation and evapotranspiration, is significantly related to annual tree ring growth, suggesting that climate may be driving tree growth trends in chronically acidified Appalachian forests. Tree ring 13C analysis from Fernow cores is underway and these data will be integrated with catchment hydrology data from five other sites in central Appalachia and the U.S. Northeast, representing a range of forest types, soil base saturations, and acid deposition histories. This work will advance understanding of how climate and acid deposition interact to influence forest productivity and water use efficiency, and improve our ability to model carbon and water cycling in forested ecosystems impacted by acid deposition.

A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

Science.gov (United States)

Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

2011-03-01

Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

Acid Deposition Maps in Spain

International Nuclear Information System (INIS)

Artinano, B.; Cabal, H.; Garcia, C.

1998-01-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km 2 grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs

The response of soil solution chemistry in European forests to decreasing acid deposition.

Science.gov (United States)

Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

2018-03-31

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S

Science.gov (United States)

Gregory B. Lawrence; Paul W. Hazlett; Ivan J. Fernandez; Rock Ouimet; Scott W. Bailey; Walter C. Shortle; Kevin T. Smith; Michael R. Antidormi

2015-01-01

Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been...

Do uric acid deposits in zooxanthellae function as eye-spots?

Directory of Open Access Journals (Sweden)

Hiroshi Yamashita

2009-07-01

Full Text Available The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Do uric acid deposits in zooxanthellae function as eye-spots?

Science.gov (United States)

Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

2009-07-17

The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

Science.gov (United States)

Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

2016-04-01

Invasive species can exhibit allelopathic effects on native species. Meanwhile, the types of acid deposition are gradually changing. Thus, the allelopathic effects of invasive species on seed germination and growth of native species may be altered or even enhanced under conditions with diversified acid deposition. This study aims to assess the allelopathic effects (using leaves extracts) of invasive plant Solidago canadensis on seed germination and growth of native species Lactuca sativa treated with five types of acid deposition with different SO4(2-) to NO3(-) ratios (1:0, sulfuric acid; 5:1, sulfuric-rich acid; 1:1, mixed acid; 1:5, nitric-rich acid; 0:1, nitric acid). Solidago canadensis leaf extracts exhibited significantly allelopathic effects on germination index, vigor index, and germination rate index of L. sativa. High concentration of S. canadensis leaf extracts also similarly exhibited significantly allelopathic effects on root length of L. sativa. This may be due to that S. canadensis could release allelochemicals and then trigger allelopathic effects on seed germination and growth of L. sativa. Acid deposition exhibited significantly negative effects on seedling biomass, root length, seedling height, germination index, vigor index, and germination rate index of L. sativa. This may be ascribed to the decreased soil pH values mediated by acid deposition which could produce toxic effects on seedling growth. Sulfuric acid deposition triggered more toxic effects on seedling biomass and vigor index of L. sativa than nitric acid deposition. This may be attributing to the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects mediated by nitric deposition. All types of acid deposition significantly enhanced the allelopathic effects of S. canadensis on root length, germination index, vigor index, and germination rate index of L. sativa. This may be due to the negatively synergistic effects of

Theory of acid deposition and its application to the dew-point meter

Energy Technology Data Exchange (ETDEWEB)

Land, T.

1977-06-01

The theory of convective mass transfer is used to calculate the rate of deposition of sulphuric acid on cooled surfaces in boiler flues. The mass deposited per unit area per second is ah/c (p/sub Ag/ - p/sub As/) where h is the coefficient of convective heat transfer, c is the specific heat of the gas and a is a factor having a value of about 1.9; p/sub Ag/ and p/sub As/ are the partial pressures of sulphuric acid in the bulk of the gas and in saturated gas at the temperature of the surface. Values of p/sub A/ are tabulated against dew-point temperature and water vapour content. The theory explains how fog formation in the gas reduces the rate of acid deposition within a certain band of temperature between the acid dew-point and the water dew-point. The rate of deposition on a probe is shown to depend on the local mass flow as well as on the acid content. By contrast the dew-point depends only on the acid content. The sensitivity of the dew-point meter to changes in acid content is not very high but it is adequate for the control of combustion. A continuously recording dew-point meter is being successfully used on industrial boilers.

Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

Science.gov (United States)

Battler, Melissa M.; Osinski, Gordon R.; Lim, Darlene S. S.; Davila, Alfonso F.; Michel, Frederick A.; Craig, Michael A.; Izawa, Matthew R. M.; Leoni, Lisa; Slater, Gregory F.; Fairén, Alberto G.; Preston, Louisa J.; Banerjee, Neil R.

2013-06-01

Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ˜100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m × 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-ray diffraction and inductively coupled plasma emission spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarosite-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite

Potential research money available from the Acid Deposition Program and Alberta Environment

International Nuclear Information System (INIS)

Primus, C.L.

1992-01-01

It is exceedingly difficult to demonstrate definitive long-term changes in animal health as a result of acid-forming emissions from sour gas wells. A summary is presented of current research in Alberta, followed by the potential for research funding by the Alberta Government/Industry Acid Deposition Program (ADRP). The Alberta Environment research budget consists of four programs in addition to the ADRP: acid deposition effects research in the Athabasca oil sands; western and northern Canada long-range transport of air pollutants; departmental monitoring; and inhalation toxicology and animal health. Animal health research, although a component of the acid deposition issue, is beyond the mandate of Alberta Environment, and the ADRP members committee does not forsee becoming involved in the long-term and complex research required to address the effects of acid-forming emissions on livestock. Funds for additional animal health research must come from other government departments and agencies whose mandate covers this area

Acidic precipitation. Volume 3: Sources, deposition, and canopy interactions. Advances in environmental science

Energy Technology Data Exchange (ETDEWEB)

Lindberg, S.E.; Page, A.L.; Norton, S.A. (eds.)

1990-01-01

As has been the case with many environmental issues of the twentieth century, acidic precipitation has its origin in emissions to the atmosphere of numerous compounds from both natural and man-made sources. This volume emphasizes the atmospheric aspects of acidic precipitation and all that this term has come to include (e.g. toxic gases such as ozone, trace metals, aluminum, and oxides of nitrogen). It progresses from emissions of the precursors of acidic precipitation to their eventual deposition on environmental surfaces. The chapters describe the sources of acidic and basic airborne substances, their interactions in the atmosphere and with rain droplets, and their reactions with other airborne constituents such as aluminum and other metals. Also discussed are the use of metals as tracers of sources of the precursors of acidic precipitation and as tracers of historical deposition rates, the processes controlling the removal of airborne material as dry deposition and deposition interactions with the forest canopy, and past and future trends in atmospheric emissions and options for their abatement.

Absorption characteristics of Kupravas deposit clays modified by phosphoric acid

International Nuclear Information System (INIS)

Ruplis, A.; Mezinskis, G.; Chaghuri, M.

1998-01-01

Literature data suggested that clays may be used as sorbents for waste water treatment. The surface and sorption properties of minerals changes due to the influence of acid rains. The process of recession of clay properties has been modeled in laboratory by treatment of clays with mineral acids at higher temperature that in natural conditions. The present paper is devoted to the study of influence of phosphoric acid on the sorption properties of Kupravas deposit clays. Natural clay samples and samples treated with phosphoric acid were characterized by means of x-ray diffraction an differential thermal analysis (DTA) methods These methods were used also to identify the sample of Lebanese clays. X-ray diffraction analysis data show that the samples of clays from the deposit of Kuprava contain illite and kaolinite while sample of Lebanese clay contains quartz, calcite, and montmorillonite. DTA results show characteristic features of Kuprava clays described in reference with DTA of Lebanese clay clearly demonstrate the presence of large quantity of calcite

Acidic deposition in California: findings from a program of monitoring and effects research

Energy Technology Data Exchange (ETDEWEB)

Takemoto, B.K.; Croes, B.E.; Brown, S.M.; Motallebi, N.; Westerdahl, F.D.; Margolis, H.G.; Cahill, B.T.; Mueller, M.D.; Holmes, J.R. [California Environmental Protection Agency, Sacramento, CA (United States). Research Division

1995-12-01

California`s 14-year, 25 million dollar acidic deposition program has studied the causes and effects of acidic air pollutants. In contrast to the eastern United States where sulfur-derived (S-derived) by-products from coal combustion dominate precipitation chemistry, nitrogen-derived (N-derived) acids predominate in wet and dry deposition in California. Adverse effects on the human lung have not been observed after short-term exposures to acidity, but extended exposures to ambient acidity may pose a chronic risk. No irreversible, adverse effects on surface waters in the Sierra Nevada mountain range or to the state`s forests have been found due to extent acidic inputs. The longer-term outlook for forests is less certain because the impacts observed elsewhere occurred after decades of S and N deposition, but at lower ambient ozone levels. Ozone is the major air pollutant stressor for forests, but atmospheric N has the potential to cause adverse changes in soil nutrient cycling. Impacts on man-made materials in southern California (e.g. galvanized steel) were found to be minor. While California does not have an ambient air quality standard for acidic air pollutants, emission of precursors have declined since the 1960s due to changes in industrial practices, improvements in technology and adoption of control measures for ozone. Lowering emission from motor vehicles will be emphasized to prevent future increases in N deposition. 67 refs., 4 figs., 2 tabs.

The distribution of common construction materials at risk to acid deposition in the United States

Science.gov (United States)

Lipfert, Frederick W.; Daum, Mary L.

Information on the geographic distribution of various types of exposed materials is required to estimate the economic costs of damage to construction materials from acid deposition. This paper focuses on the identification, evaluation and interpretation of data describing the distributions of exterior construction materials, primarily in the United States. This information could provide guidance on how data needed for future economic assessments might be acquired in the most cost-effective ways. Materials distribution surveys from 16 cities in the U.S. and Canada and five related databases from government agencies and trade organizations were examined. Data on residential buildings are more commonly available than on nonresidential buildings; little geographically resolved information on distributions of materials in infrastructure was found. Survey results generally agree with the appropriate ancillary databases, but the usefulness of the databases is often limited by their coarse spatial resolution. Information on those materials which are most sensitive to acid deposition is especially scarce. Since a comprehensive error analysis has never been performed on the data required for an economic assessment, it is not possible to specify the corresponding detailed requirements for data on the distributions of materials.

An overview of a 5-year research program on acid deposition in China

Science.gov (United States)

Wang, T.; He, K.; Xu, X.; Zhang, P.; Bai, Y.; Wang, Z.; Zhang, X.; Duan, L.; Li, W.; Chai, F.

2011-12-01

Despite concerted research and regulative control of sulfur dioxide in China, acid rain remained a serious environmental issue, due to a sharp increase in the combustion of fossil fuel in the 2000s. In 2005, the Ministry of Science and Technology of China funded a five-year comprehensive research program on acid deposition. This talk will give an overview of the activities and the key findings from this study, covering emission, atmospheric processes, and deposition, effects on soil and stream waters, and impact on typical trees/plants in China. The main results include (1) China still experiences acidic rainfalls in southern and eastern regions, although the situation has stabilized after 2006 due to stringent control of SO2 by the Chinese Government; (2) Sulfate is the dominant acidic compound, but the contribution of nitrate has increased; (3) cloud-water composition in eastern China is strongly influenced by anthropogenic emissions; (4) the persistent fall of acid rain in the 30 years has lead to acidification of some streams/rivers and soils in southern China; (5) the studied plants have shown varying response to acid rain; (6) some new insights have been obtained on atmospheric chemistry, atmospheric transport, soil chemistry, and ecological impacts, some of which will be discussed in this talk. Compared to the situation in North America and Europe, China's acid deposition is still serious, and continued control of sulfur and nitrogen emission is required. There is an urgent need to establish a long-term observation network/program to monitor the impact of acid deposition on soil, streams/rivers/lakes, and forests.

Acid atmospheric deposition in a forested mountain catchment

Czech Academy of Sciences Publication Activity Database

Křeček, J.; Palán, L.; Stuchlík, Evžen

2017-01-01

Roč. 10, č. 4 (2017), s. 680-686 ISSN 1971-7458 Institutional support: RVO:60077344 Keywords : mountain water shed * spruce forests * acid atmospheric deposition * water resources recharge Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 1.623, year: 2016

Urban acid deposition. Results from the GMADS network, 1990

Energy Technology Data Exchange (ETDEWEB)

Conlan, D.E.; Longhurst, J.W.S.; Gee, D.R.; Hare, S.E.

1991-07-01

This fourth annual data report of the Greater Manchester Acid Deposition Survey (GMADS) gives results from the urban precipitation chemistry network across Greater Manchester and Warrington for 1990. Full analytical methods are described along with precision and accuracy of the methods used. The spatial variability of precipitation chemistry and deposition over this urban region was investigated using a network of twenty collectors. Concentrations of non marine sulphate, ammonium, calcium and hydrogen, and nitrogen dioxide gas concentrations all show significant spatial variability. The spatial variability of the deposition rates of non marine sulphate, nitrate, ammonium, hydrogen and calcium were significant. 40 refs., 13 figs., 9 tabs., 1 app.

Analysis of potential combustion source impacts on acid deposition using an independently derived inventory. Volume I

Energy Technology Data Exchange (ETDEWEB)

1983-12-01

This project had three major objectives. The first objective was to develop a fossil fuel combustion source inventory (NO/sub x/, SO/sub x/, and hydrocarbon emissions) that would be relatively easy to use and update for analyzing the impact of combustion emissions on acid deposition in the eastern United States. The second objective of the project was to use the inventory data as a basis for selection of a number of areas that, by virtue of their importance in the acid rain issue, could be further studied to assess the impact of local and intraregional combustion sources. The third objective was to conduct an analysis of wet deposition monitoring data in the areas under study, along with pertinent physical characteristics, meteorological conditions, and emission patterns of these areas, to investigate probable relationships between local and intraregional combustion sources and the deposition of acidic material. The combustion source emissions inventory has been developed for the eastern United States. It characterizes all important area sources and point sources on a county-by-county basis. Its design provides flexibility and simplicity and makes it uniquely useful in overall analysis of emission patterns in the eastern United States. Three regions with basically different emission patterns have been identified and characterized. The statistical analysis of wet deposition monitoring data in conjunction with emission patterns, wind direction, and topography has produced consistent results for each study area and has demonstrated that the wet deposition in each area reflects the characteristics of the localized area around the monitoring sites (typically 50 to 150 miles). 8 references, 28 figures, 39 tables.

Acidic deposition: State of science and technology. Report 10. Watershed and lake processes affecting surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Turner, R.S.; Cook, R.B.; Miegroet, H.V.; Johnson, D.W.; Elwood, J.W.

1990-09-01

The acid-base chemistry of surface waters is governed by the amount and chemistry of deposition and by the biogeochemical reactions that generate acidity or acid neutralizing capacity (ANC) along the hydrologic pathways that water follows through watersheds to streams and lakes. The amount of precipitation and it chemical loading depend on the area's climate and physiography, on it proximity to natural or industrial gaseous or particulate sources, and on local or regional air movements. Vegetation interacts with the atmosphere to enhance both wet and dry deposition of chemicals to a greater or lesser extent, depending on vegetation type. Vegetation naturally acidifies the environment in humid regions through processes of excess base cation uptake and generation of organic acids associated with many biological processes. Natural acid production and atmospheric deposition of acidic materials drive the acidification process. The lake or stream NAC represents a balance between the acidity-and ANC-generating processes that occur along different flow paths in the watershed and the relative importance of each flow path

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben

2009-07-28

We used a general circulation model of Earth\\'s climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.; Marquardt, Allison B.

2009-01-01

We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

The Contribution from Shipping Emissions to Air Quality and Acid Deposition in Europe

International Nuclear Information System (INIS)

Derwent, Richard G.; Stevenson, David S.; Doherty, Ruth M.; Cofala, Janusz; Mechler, Reinhard; Amann, Markus; Dentener, Frank J.

2005-01-01

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO 2 , NO x , VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m-2 yr-1 over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria

2013-04-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged layers of layered double hydroxides (LDHs) modified with ionic liquids (ILs) and the negatively charged plasma treated polylactic acid leads to homogeneous, stable, and highly durable coatings. Deposition of the LDH coatings increases the surface hydrophobicity of the neat PLA, which results to a decrease in water permeability by about 35%. © 2013 Elsevier Inc.

Acidic deposition: State of science and technology. Report 9. Current status of surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Baker, L.A.; Kaufmann, P.R.; Brakke, D.F.; Herlihy, A.T.; Eilers, J.M.

1990-09-01

The report is based largely upon the National Surface Water Survey (NSWS), augmented by numerous smaller state and university surveys and many detailed watershed studies. In describing the current status of surface waters, the authors go far beyond the description of population statistics, although some of this is necessary, and direct their attention to the interpretation of these data. They address the question of the sources of acidity to surface waters in order to determine the relative importance of acidic deposition compared with other sources, such as naturally produced organic acids and acid mine drainage. They also examine in some detail what they call 'high interest' populations-the specific groups of lakes and streams most likely to be impacted by acidic deposition. The authors then turn to the general question of uncertainty, and finally examine low alkalinity surface waters in several other parts of the world to develop further inferences about the acid-base status of surface waters in the United States

Influence of containing of asphaltenes and naphthenic acids over organic deposition inhibitor performance

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Geiza E.; Mansur, Claudia R.E.; Pires, Renata V.; Passos, Leonardo B.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas; Alvares, Dellyo R.S.; Gonzalez, Gaspar [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

Organic deposition is a serious problem confronted by the petroleum industry in Brazil and worldwide. Among the main petroleum components that may cause deposition problems are waxes and asphaltenes. This work aims at evaluating the influence of petroleum fractions (asphaltenes and naphthenic acids) on the organic deposition phenomenon as well as on organic deposition inhibitors performance. The influence of the organic fractions was evaluated by their ability to change wax crystals, to lower the pour point and to alter the initial wax appearance temperature. The efficiency of the additives was tested by pour point measurements. The results show that asphaltenes seem to act as organic deposition inhibitors, while naphthenic acids do not significantly change the system. Moreover, employing both of them produces no synergic effect. Among polymeric inhibitors, all of the chemically modified EVA copolymer presented better results than the non-modified commercial EVA copolymer. The best result was observed for EVA28C{sub 16}. (author)

Factors affecting the long-term response of surface waters to acidic deposition: state-of-the-science

Energy Technology Data Exchange (ETDEWEB)

Turner, R.S.; Johnson, D.W.; Elwood, J.N.; Van Winkle, W.; Clapp, R.B.; Jones, M.L.; Marmarek, D.R.; Thornton, K.W.; Gherinig, S.A.; Schnoor, J.L.

1986-01-01

Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable minerals (weathering rates), depth of till, micropore flow, and type of forest cover. Correlative and predictive models have been developed to show the relationships (if any) between hypothesized controlling mechanisms and surface water acidity, and to suggest under what conditions additional surface water might become acid. This document (Part A) is a review of our current knowledge of factors and processes controlling soil and surface water acidification, as well as an assessment of the adequacy of that knowledge for making predictions of future acidification. Section 2 is a data extensive, conceptual overview of how watersheds function. Section 3 is a closer look at the theory and evidence for the key hypotheses. Section 4 is a review of existing methods of assessing system response to acidic deposition.

Measurements of dry-deposition parameters for the California acid-deposition monitoring program. Final report

International Nuclear Information System (INIS)

Watson, J.G.; Chow, J.C.; Egami, R.T.; Bowen, J.L.; Frazier, C.A.

1991-06-01

The State of California monitors the concentrations of acidic gases and particles at 10 sites throughout the state. Seven sites represent urban areas (South Coast Air Basin - three sites, San Francisco Bay Area, Bakersfield, Santa Barbara, and Sacramento) and three represent forested areas (Sequoia National Park, Yosemite National Park, and Gasquet). Several sites are collocated with monitoring instruments for other air quality and forest response networks. Continuous monitors for the dry deposition network collect hourly average values for ozone, wind speed, wind direction, atmospheric stability, temperature, dew point, time of wetness, and solar radiation. A newly-designed gas/particle sampler collects daytime (6 a.m. to 6 p.m.) and nighttime (6 p.m. to 6 a.m.) samples every sixth day for sulfur dioxide, ammonia, nitrogen dioxide, and nitric acid. Particles are collected on the same day/night schedule in PM(10) and PM(2.5) size ranges, and are analyzed for mass, sulfate, nitrate, chloride, ammonium, sodium, magnesium, potassium, and calcium ions. The sampling schedule follows the regulatory schedule adopted by the EPA and ARB for suspended particulate matter. Wet deposition data are collected at or nearby the dry deposition stations. The first year of the monitoring program included installation of the network, training of technicians, acquisition and validation of data, and transfer of the sampling and analysis technology to Air Resources Board operating divisions. Data have been validated and stored for the period May, 1988 through September, 1989

Urban wet deposition nitrate: a comparison to non-urban deposition

International Nuclear Information System (INIS)

Schultz, J.A.M.

1994-01-01

The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO x . Since NO x is produced in amounts comparable to SO 2 , it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment. 24 refs., 2 figs., 2 tabs

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

Energy Technology Data Exchange (ETDEWEB)

Stevens, Carly J., E-mail: c.j.stevens@open.ac.uk [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Dupre, Cecilia [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Dorland, Edu [Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, PO Box 80.058, 3508 TB Utrecht (Netherlands); Gaudnik, Cassandre [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Gowing, David J.G. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Bleeker, Albert [Department of Air Quality and Climate Change, Energy Research Centre of the Netherlands, PO Box 1, 1755 ZG Petten (Netherlands); Diekmann, Martin [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Alard, Didier [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Bobbink, Roland [B-WARE Research Centre, Radboud University, PO Box 9010, 6525 ED Nijmegen (Netherlands); Fowler, David [NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Corcket, Emmanuel [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Mountford, J. Owen [NERC Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Vandvik, Vigdis [Department of Biology, University of Bergen, Box 7800, N-5020 Bergen (Norway)

2011-10-15

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha{sup -1} yr{sup -1}) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: > N deposition is negatively correlated with forb richness as a proportion of species richness. > Soil C:N ratio increased with increasing N deposition. > Soil extractable nitrate and ammonium were not related to nitrogen deposition. > Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

International Nuclear Information System (INIS)

Stevens, Carly J.; Dupre, Cecilia; Dorland, Edu; Gaudnik, Cassandre; Gowing, David J.G.; Bleeker, Albert; Diekmann, Martin; Alard, Didier; Bobbink, Roland; Fowler, David; Corcket, Emmanuel; Mountford, J. Owen; Vandvik, Vigdis

2011-01-01

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha -1 yr -1 ) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: → N deposition is negatively correlated with forb richness as a proportion of species richness. → Soil C:N ratio increased with increasing N deposition. → Soil extractable nitrate and ammonium were not related to nitrogen deposition. → Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

Impact of acid atmosphere deposition on soils : field monitoring and aluminum chemistry

NARCIS (Netherlands)

Mulder, J.

1988-01-01

The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions

Acid-deposition research program. Volume 2. Effects of acid-forming emissions on soil microorganisms and microbially-mediated processes

Energy Technology Data Exchange (ETDEWEB)

Visser, S.; Danielson, R.M.; Parr, J.F.

1987-02-01

The interactions of soil physical, chemical, and biological processes are ultimately expressed in a soil's fertility and its capacity for plant production. Consequently, much of the research conducted to date regarding the impact of acid-forming pollutants on soil properties has been geared towards possible effects on plant productivity. This trend continues in this paper where the effects of acidic deposition on microbial communities are reviewed in relation to potential impact on plant growth. The objectives of the review are to discuss: (1) The effects of acid-forming emissions (primarily S-containing pollutants) on microbial community structure with emphasis on qualitative and quantitative aspects; (2) The effects of acidic deposition on microbially mediated processes (i.e., community functions); (3) Acidification effects of pollutants on symbiotic and disease-causing microorganisms. The symbionts discussed include ectomycorrhizal fungi, vesicular-arbuscular mycorrhizal fungi, and N/sub 2/-fixing bacteria, particularly Rhizobium, while the disease-causing microorganisms will include those responsible for foliage, stem, and root diseases.

Intensified Vegetation Water Use due to Soil Calcium Leaching under Acid Deposition

Science.gov (United States)

Lanning, M.; Wang, L.; Scanlon, T. M.; Vadeboncoeur, M. A.; Adams, M. B.; Epstein, H. E.; Druckenbrod, D.

2017-12-01

Despite the important role vegetation plays in the global water cycle, the exact controls of vegetation water use, especially the role of soil biogeochemistry, remain elusive. Nitrate and sulfate deposition from fossil fuel burning has caused significant soil acidification, leading to the leaching of soil base cations. From a physiological perspective, plants require various soil cations as signaling and regulatory ions as well as integral parts of structural molecules; a depletion of soil cations can cause reduced productivity and abnormal responses to environmental change. A deficiency in calcium could also potentially prolong stomatal opening, leading to increased transpiration until enough calcium had been acquired to stimulate stomatal closure. Based on the plant physiology and the nature of acidic deposition, we hypothesize that depletion of the soil calcium supply, induced by acid deposition, would intensify vegetation water use at the watershed scale. We tested this hypothesis by analyzing a long-term and unique data set (1989-2012) of soil lysimeter data along with stream flow and evapotranspiration data at the Fernow Experimental Forest. We show that depletion of soil calcium by acid deposition can intensify vegetation water use ( 10% increase in evapotranspiration and depletion in soil water) for the first time. These results are critical to understanding future water availability, biogeochemical cycles, and surficial energy flux and may help reduce uncertainties in terrestrial biosphere models.

Effects of decreasing acid deposition and climate change on acid extremes in an upland stream

Directory of Open Access Journals (Sweden)

C. D. Evans

2008-03-01

Full Text Available This study assesses the major chemical processes leading to acid extremes in a small, moorland stream in mid-Wales, UK, which has been monitored since 1979. Results suggest that base cation (mainly calcium dilution, the "sea-salt effect", and elevated nitrate pulses, are the major causes of seasonal/episodic minima in acid neutralising capacity (ANC, and that the relative importance of these drivers has remained approximately constant during 25 years of decreasing acid deposition and associated long-term chemical recovery. Many of the chemical variations causing short-term reductions in stream acidity, particularly base cation dilution and organic acid increases, are closely related to changes in water-flowpath and therefore to stream discharge. Changes in the observed pH-discharge relationship over time indicate that high-flow pH has increased more rapidly than mean-flow pH, and therefore that episodes have decreased in magnitude since 1980. However a two-box application of the dynamic model MAGIC, whilst reproducing this trend, suggests that it will not persist in the long term, with mean ANC continuing to increase until 2100, but the ANC of the upper soil (the source of relatively acid water during high-flow episodes stabilising close to zero beyond 2030. With climate change predicted to lead to an increase in maximum flows in the latter half of the century, high-flow related acid episodes may actually become more rather than less severe in the long term, although the model suggests that this effect may be small. Two other predicted climatic changes could also detrimentally impact on acid episodes: increased severity of winter "sea-salt" episodes due to higher wind speeds during winter storms; and larger sulphate pulses due to oxidation of reduced sulphur held in organic soils, during more extreme summer droughts. At the Gwy, the near-coastal location and relatively small extent of peat soils suggest that sea-salt episodes may have the

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; McPherson, G.T.

2013-01-01

This study documents the effects of acidic deposition and soil acid-base chemistry on the growth, regeneration, and canopy condition of sugar maple (SM) trees in the Adirondack Mountains of New York. Sugar maple is the dominant canopy species throughout much of the northern hardwood forest in the State. A field study was conducted in 2009 in which 50 study plots within 20 small Adirondack watersheds were sampled and evaluated for soil acid-base chemistry and SM growth, canopy condition, and regeneration. Atmospheric sulfur (S) and nitrogen (N) deposition were estimated for each plot. Trees growing on soils with poor acid-base chemistry (low exchangeable calcium and % base saturation) that receive relatively high levels of atmospheric S and N deposition exhibited little to no SM seedling regeneration, decreased canopy condition, and short-to long-term growth declines compared with study plots having better soil condition and lower levels of atmospheric deposition. These results suggest that the ecosystem services provided by SM in the western and central Adirondack Mountain region, including aesthetic, cultural, and monetary values, are at risk from ongoing soil acidification caused in large part by acidic deposition.

Photosynthesis and oxidative stress in the restinga plant species Eugenia uniflora L. exposed to simulated acid rain and iron ore dust deposition: Potential use in environmental risk assessment

Energy Technology Data Exchange (ETDEWEB)

Rust Neves, Natalia; Oliva, Marco Antonio; Cruz Centeno, Danilo da; Costa, Alan Carlos; Ferreira Ribas, Rogerio [Departamento de Biologia Vegetal, Universidade Federal de Vicosa, Av. PH Rolfs, Campus, Vicosa, Minas Gerais, 36570-000 (Brazil); Gusmao Pereira, Eduardo, E-mail: egpereira@gmail.com [Departamento de Biologia Vegetal, Universidade Federal de Vicosa, Av. PH Rolfs, Campus, Vicosa, Minas Gerais, 36570-000 (Brazil)

2009-06-01

The Brazilian sandy coastal plain named restinga is frequently subjected to particulate and gaseous emissions from iron ore factories. These gases may come into contact with atmospheric moisture and produce acid rain. The effects of the acid rain on vegetation, combined with iron excess in the soil, can lead to the disappearance of sensitive species and decrease restinga biodiversity. The effects of iron ore dust deposition and simulated acid rain on photosynthesis and on antioxidant enzymes were investigated in Eugenia uniflora, a representative shrub species of the restinga. This study aimed to determine the possible utility of this species in environmental risk assessment. After the application of iron ore dust as iron solid particulate matter (SPM{sub Fe}) and simulated acid rain (pH 3.1), the 18-month old plants displayed brown spots and necrosis, typical symptoms of iron toxicity and injuries caused by acid rain, respectively. The acidity of the rain intensified leaf iron accumulation, which reached phytotoxic levels, mainly in plants exposed to iron ore dust. These plants showed the lowest values for net photosynthesis, stomatal conductance, transpiration, chlorophyll a content and electron transport rate through photosystem II (PSII). Catalase and superoxide dismutase activities were decreased by simulated acid rain. Peroxidase activity and membrane injury increased following exposure to acid rain and simultaneous SPM{sub Fe} application. Eugenia uniflora exhibited impaired photosynthetic and antioxidative metabolism in response to combined iron and acid rain stresses. This species could become a valuable tool in environmental risk assessment in restinga areas near iron ore pelletizing factories. Non-invasive evaluations of visual injuries, photosynthesis and chlorophyll a fluorescence, as well as invasive biochemical analysis could be used as markers.

Photosynthesis and oxidative stress in the restinga plant species Eugenia uniflora L. exposed to simulated acid rain and iron ore dust deposition: Potential use in environmental risk assessment

International Nuclear Information System (INIS)

Rust Neves, Natalia; Oliva, Marco Antonio; Cruz Centeno, Danilo da; Costa, Alan Carlos; Ferreira Ribas, Rogerio; Gusmao Pereira, Eduardo

2009-01-01

The Brazilian sandy coastal plain named restinga is frequently subjected to particulate and gaseous emissions from iron ore factories. These gases may come into contact with atmospheric moisture and produce acid rain. The effects of the acid rain on vegetation, combined with iron excess in the soil, can lead to the disappearance of sensitive species and decrease restinga biodiversity. The effects of iron ore dust deposition and simulated acid rain on photosynthesis and on antioxidant enzymes were investigated in Eugenia uniflora, a representative shrub species of the restinga. This study aimed to determine the possible utility of this species in environmental risk assessment. After the application of iron ore dust as iron solid particulate matter (SPM Fe ) and simulated acid rain (pH 3.1), the 18-month old plants displayed brown spots and necrosis, typical symptoms of iron toxicity and injuries caused by acid rain, respectively. The acidity of the rain intensified leaf iron accumulation, which reached phytotoxic levels, mainly in plants exposed to iron ore dust. These plants showed the lowest values for net photosynthesis, stomatal conductance, transpiration, chlorophyll a content and electron transport rate through photosystem II (PSII). Catalase and superoxide dismutase activities were decreased by simulated acid rain. Peroxidase activity and membrane injury increased following exposure to acid rain and simultaneous SPM Fe application. Eugenia uniflora exhibited impaired photosynthetic and antioxidative metabolism in response to combined iron and acid rain stresses. This species could become a valuable tool in environmental risk assessment in restinga areas near iron ore pelletizing factories. Non-invasive evaluations of visual injuries, photosynthesis and chlorophyll a fluorescence, as well as invasive biochemical analysis could be used as markers.

Arc-related porphyry molybdenum deposit model: Chapter D in Mineral deposit models for resource assessment

Science.gov (United States)

Taylor, Ryan D.; Hammarstrom, Jane M.; Piatak, Nadine M.; Seal, Robert R.

2012-01-01

This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which is intended to supplement previously published models for this deposit type that help guide mineral-resource and mineral-environmental assessments.

Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

Indian Academy of Sciences (India)

Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

Acidic deposition and its effects on forest productivity: a review of the present state of knowledge, research activities, and information needs

Energy Technology Data Exchange (ETDEWEB)

Pinkerton, J.E.

1981-01-01

The present state of knowledge with regard to acid deposition is reviewed. Sources include the literature and direct contact with persons responsible for carrying out all completed, ongoing, and planned research activities, national and international, related to acidic deposition and its effects, with emphasis on forest productivity. In addition, a list of information needs in seven areas was developed, these include: a characterization of forest soils to define their sensitivity to acidic deposition; effects on forest soil chemical and biological processes; development of improved dry deposition measurement methods; changes in precipitation composition due to forest canopies; more extensive monitoring of acidic deposition in industry owned forest lands; expansion of long-term greenhouse and controlled field experiments; and the relationship of acidic deposition and intensive forestry management practices. 85 references. (MDF)

Acid deposition: a select review 1852-1990. 2. Effects on materials and health; abatement strategies and programmes

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Raper, D.W.; Lee, D.S.; Heath, B.A.; Conlan, B.; King, H.J. (Manchester Metropolitan University, Manchester (United Kingdom). Atmospheric Research and Information Centre)

1993-10-01

Part 2 of this review is concerned with the impact of acid deposits and their precursors on materials and human health, and with the control technologies and programmes introduced as a consequence of the environmental impacts of acid deposition. 269 refs., 8 figs., 8 tabs.

Acid deposition: State of science and technology. Summary report of the U.S. National Acid Precipitation Assessment Program

International Nuclear Information System (INIS)

Irving, P.M.; Smith, E.

1991-09-01

The twenty-seven State-of-Science and State-of-Technology (SOS/T) Reports, published in 1990 as the definitive scientific and technical synthesis of information obtained during the first decade of the U.S. national Acid Precipitation Assessment Program (NAPAP), are summarized in the document. In most cases, these summaries were the final chapter of the complete SOS/T Report

Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

Energy Technology Data Exchange (ETDEWEB)

Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

2004-05-24

Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

Influence of Humic Acid on the Transport and Deposition of Colloidal Silica under Different Hydrogeochemical Conditions

Directory of Open Access Journals (Sweden)

Jingjing Zhou

2016-12-01

Full Text Available The transport and deposition of colloids in aquifers plays an important role in managed aquifer recharge (MAR schemes. Here, the processes of colloidal silica transport and deposition were studied by displacing groundwater with recharge water. The results showed that significant amounts of colloidal silica transport occurred when native groundwater was displaced by HA solution. Solution contains varying conditions of ionic strength and ion valence. The presence of humic acid could affect the zeta potential and size of the colloidal silica, which led to obvious colloidal silica aggregation in the divalent ion solution. Humic acid increased colloidal silica transport by formation of non-adsorbing aqueous phase silica–HA complexes. The experimental and modeling results showed good agreement, indicating that the essential physics were accurately captured by the model. The deposition rates were less than 10−8 s−1 in deionized water and monovalent ion solution. Moreover, the addition of Ca2+ and increase of IS resulted in the deposition rates increasing by five orders of magnitude to 10−4 s−1. In all experiments, the deposition rates decreased in the presence of humic acid. Overall, the promotion of humic acid in colloidal silica was strongly associated with changes in water quality, indicating that they should receive greater attention during MAR.

The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

Directory of Open Access Journals (Sweden)

S. A. Watmough

2002-01-01

Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

Effects of acid and alkaline based surface preparations on spray deposited cerium based conversion coatings on Al 2024-T3

Energy Technology Data Exchange (ETDEWEB)

Pinc, W. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)], E-mail: wrphw5@mst.edu; Geng, S.; O' Keefe, M.; Fahrenholtz, W.; O' Keefe, T. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

2009-01-15

Cerium based conversion coatings were spray deposited on Al 2024-T3 and characterized to determine the effect of surface preparation on the deposition rate and surface morphology. It was found that activation of the panel using a 1-wt.% sulfuric acid solution increased the coating deposition rate compared to alkaline cleaning alone. Analysis of the surface morphology of the coatings showed that the coatings deposited on the acid treated panels exhibited fewer visible cracks compared to coatings on alkaline cleaned panels. Auger electron spectroscopy depth profiling showed that the acid activation decreased the thickness of the aluminum oxide layer and the concentration of magnesium on the surface of the panels compared to the alkaline treatment. Additionally, acid activation increased the copper concentration at the surface of the aluminum substrate. Based on the results, the acid based surface treatment appeared to expose copper rich intermetallics, thus increasing the number of cathodic sites on the surface, which led to an overall increase in the deposition rate.

Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

Science.gov (United States)

Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

2013-01-01

Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East.More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

International Nuclear Information System (INIS)

Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

2013-01-01

Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate

Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

Science.gov (United States)

Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

2013-11-01

Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

Differences in functional traits between invasive and native Amaranthus species under simulated acid deposition with a gradient of pH levels

Science.gov (United States)

Wang, Congyan; Wu, Bingde; Jiang, Kun; Zhou, Jiawei

2018-05-01

Co-occurring invasive plant species (invaders hereafter) and natives receive similar or even the same environmental selection pressures. Thus, the differences in functional traits between natives and invaders have become widely recognized as a major driving force of the success of plant invasion. Meanwhile, increasing amounts of acid are deposited into ecosystems. Thus, it is important to elucidate the potential effects of acid deposition on the functional traits of invaders in order to better understand the potential mechanisms for the successful invasion. This study aims to address the differences in functional traits between native red amaranth (Amaranthus tricolor L.; amaranth hereafter) and invasive redroot pigweed (A. retroflexus L.; pigweed hereafter) under simulated acid deposition with a gradient of pH levels. Pigweed was significantly taller than amaranth under most treatments. The greater height of pigweed can lead to greater competitive ability for resource acquisition, particularly for sunlight. Leaf shape index of pigweed was also significantly greater than that of amaranth under all treatments. The greater leaf shape index of pigweed can enhance the efficiency of resource capture (especially sunlight capture) via adjustments to leaf shape and size. Thus, the greater height and leaf shape index of pigweed can significantly enhance its competitive ability, especially under acid deposition. Acid deposition of pH 5.6 significantly increased amaranth leaf width in the co-cultivation due to added nutrients. The pH 4.5 acid deposition treatment significantly increased the specific leaf area of amaranth in the monoculture compared with the pH 5.6 acid deposition treatment and the control. The main mechanism explaining this pattern may be due to acid deposition mediating a hormesis effect on plants, promoting plant growth. The values of the relative competition intensity between amaranth and pigweed for most functional traits were lower than zero under most

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria; Livi, Sebastien; Hayrapetyan, Suren; Wang, Yue; Estevez, Luis; Vittoria, Vittoria; Giannelis, Emmanuel P.

2013-01-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged

Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

Science.gov (United States)

Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

2003-01-01

Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

Effect of Time and Deposition Method on Quality of Phosphonic Acid Modifier Self-Assembled Monolayers on Indium Zinc Oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi; Knesting, Kristina M.; Bulusu, Anuradha; Sigdel, Ajaya K.; Giordano, Anthony J.; Marder, Seth R.; Berry, Joseph J.; Graham, Samuel; Ginger, David S.; Pemberton, Jeanne E.

2016-12-15

Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F5BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after -48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F13-octylphosphonic acid (F13OPA), and pentafluorinated benzyl phosphonic acid (F5BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48-168 h solution deposition at both room temperature and 70 degrees C result in contamination- and surface etch-free close-packed monolayers with good reproducibility. SAMs fabricated by micro-contact printing and spray coating are much less well ordered.

Steam generator deposit control program assessment at Comanche Peak

International Nuclear Information System (INIS)

Stevens, J.; Fellers, B.; Orbon, S.

2002-01-01

Comanche Peak has employed a variety of methods to assess the effectiveness of the deposit control program. These include typical methods such as an extensive visual inspection program and detailed corrosion product analysis and trending. In addition, a recently pioneered technique, low frequency eddy current profile analysis (LFEC) has been utilized. LFEC provides a visual mapping of the magnetite deposit profile of the steam generator. Analysis of the LFEC results not only provides general area deposition rates, but can also provide local deposition patterns, which is indicative of steam generator performance. Other techniques utilized include trending of steam pressure, steam generator hideout-return, and flow assisted corrosion (FAC) results. The sum of this information provides a comprehensive assessment of the deposit control program effectiveness and the condition of the steam generator. It also provides important diagnostic and predictive information relative to steam generator life management and mitigative strategies, such as special cleaning procedures. This paper discusses the techniques employed by Comanche Peak Chemistry to monitor the effectiveness of the deposit control program and describes how this information is used in strategic planning. (authors)

Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

Energy Technology Data Exchange (ETDEWEB)

Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

1996-02-01

Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

Acid rain and nitrogen deposition in a sub-tropical watershed (Piracicaba): ecosystem consequences

International Nuclear Information System (INIS)

Krusche, A.V.; Camargo, P.B. de; Cerri, C.E.; Ballester, M.V.; Lara, L.B.L.S.; Victoria, R.L.; Martinelli, L.A.

2003-01-01

Poorly buffered sandy soils may result in acidification problems for forests in this basin. - High levels of wet N and acidic deposition were measured in southeast Brazil. In this study we addressed the sensitivity of water bodies and soils to acidification and N deposition in the Piracicaba River basin (12,400 km 2 ). Average acid neutralization capacity (ANC) at 23 river sampling sites varied from 350 to 1800 μeq l -1 . Therefore, rivers and streams in the Piracicaba basin are well buffered, if the lower limit of 200 μeq l -1 is assumed as an indication of poorly buffered waters. ANC is increased by untreated wastewaters discarded into rivers and streams of the region. Average NO 3 concentrations varied from 20 to 70 μeq l -1 . At the most polluted river sites, NO 3 concentration is not highest, however, probably due to NO 3 reduction and denitrification. Most of the nitrogen in streams is also provided by wastewaters and not by wet deposition. The majority of the soils in the basin, however, are acidic with a low base cation content and high aluminum concentration. Therefore, soils in this basin are poorly buffered and, in areas of forest over sandy soils, acidification may be a problem

Effect of time and deposition method on quality of phosphonic acid modifier self-assembled monolayers on indium zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States); Knesting, Kristina M. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Bulusu, Anuradha [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Sigdel, Ajaya K. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Giordano, Anthony J.; Marder, Seth R. [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Berry, Joseph J. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Graham, Samuel [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Ginger, David S. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Pemberton, Jeanne E., E-mail: pembertn@email.arizona.edu [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States)

2016-12-15

Highlights: • Deposition of phosphonic acid monolayers on oxides from ethanol solutions occurs by rapid adsorption within 10 s with slower equilibration complete in 48 h. • The slower equilibration step involves molecular reorientation and vacancy filling on the oxide surface. • Soak-free deposition by spray coating and microcontact printing do not provide reproducible, fully-covered, uniform monolayers without substrate etching. • Adjustments to exposure time, substrate temperature, and solution/substrate contact efficiency are necessary to optimize soak-free methods. - Abstract: Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F{sub 5}BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after ∼48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F{sub 13}-octylphosphonic acid (F{sub 13}OPA), and pentafluorinated benzyl phosphonic acid (F{sub 5}BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48–168 h solution

Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees

Science.gov (United States)

Pamela E. Padgett; Hillary Cook; Andrzej Bytnerowicz; Robert L. Heath

2009-01-01

Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to...

Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

Science.gov (United States)

Taylor, Ryan D.; Anderson, Eric D.

2018-05-17

Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have been modified by metamorphism and hydrothermal fluid flow subsequent to initial sedimentation.The deposits are found exclusively within fault-bounded depositional basins. The periphery of these basins commonly consists of granite-greenstone terranes, classic hosts for lode gold that source the detrital material infilling the basin. The gold reefs are typically located along unconformities or, less commonly, at the top of sedimentary beds. Large quartz pebbles and heavy-mineral concentrates are found associated with the gold. Deposits that formed prior to the Great Oxidation Event (circa 2.4 giga-annum [Ga]) contain pyrite, whereas younger deposits contain iron oxides. Uranium minerals and hydrocarbons are also notable features of some deposits.Much of the gold in these types of deposits forms crystalline features that are the product of local remobilization. However, some gold grains preserve textures that are undoubtedly of detrital origin. Other heavy minerals, such as pyrite, contain growth banding that is truncated along broken margins, which indicates that they were transported into place as opposed to forming by in situ growth in a hydrothermal setting.The ore tailings associated with these deposits commonly contain uranium-rich minerals and sulfides. Oxidation of the sulfides releases sulfuric acid and mobilizes various metals into the environment. The neutralizing potential of the tailings is minimal, since carbonate minerals are rare. The continuity of the tabular ore bodies, such as those of the Witwatersrand Basin, has allowed these mines to be the deepest in

Sulfuric acid dissolution of the Chashma-Sang deposit's green clays

International Nuclear Information System (INIS)

Mirzoev, D.Kh.; Boboev, Kh.E.; Pulatov, M.S.; Mirsaidov, U.M.

2005-01-01

Present article is presenting the results of the roentgen phase, thermodynamic and physical-chemical investigations of the green clays of the Chashma-Sang deposit of the Republic of Tajikistan. It is presented mineralogical and chemical composition of the mineral raw materials. Kinetic of decomposition of the oxides of aluminum and iron on temperature, time and concentration of the sulfuric acid has been investigated

Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid.

Science.gov (United States)

Padgett, Pamela E; Parry, Sally D; Bytnerowicz, Andrzej; Heath, Robert L

2009-01-01

Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric acid follow? We investigated the effects of dry deposition of nitric acid on the foliage of four tree species native to the western United States. A novel controlled environment, fumigation system enabled a four-week exposure at concentrations consistent with ambient diurnal patterns. Scanning electron microscopy and automated image analysis revealed changes in the epicuticular wax layer during fumigation. Exposure to nitric acid resulted in a reproducible suite of damage symptoms that increased with increasing dose. Each tree species tested exhibited a unique set of damage features, including cracks, lesions, and conformation changes to epicuticular crystallite structures. Dry deposition of atmospheric nitric acid caused substantial perturbation to the epicuticular surface of all four tree species investigated, consistent with the chemical oxidation of epicuticular waxes. Automated image analysis eliminated many biases that can trouble microscopy studies. Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.

U(VI) speciation and reduction in acid chloride fluids in hydrothermal conditions: from transport to deposition of uranium in unconformity-related deposits

International Nuclear Information System (INIS)

Dargent, Maxime

2014-01-01

Circulations of acidic chloride brines in the earth's crust are associated with several types of uranium deposits, particularly unconformity-related uranium (URU) deposits. The spectacular high grade combined with the large tonnage of these deposits is at the origin of the key questions concerning the geological processes responsible for U transport and precipitation. The aim of this work is to performed experimental studies of U(VI) speciation and its reduction to U(IV) subsequently precipitation to uraninite under hydrothermal condition. About uranium transport, the study of U(VI) speciation in acidic brines at high temperature is performed by Raman and XAS spectroscopy, showing the coexistence of several uranyl chloride complexes UO 2 Cl n 2-n (n = 0 - 5). From this study, complexation constants are proposed. The strong capability of chloride to complex uranyl is at the origin of the transport of U(VI) at high concentration in acidic chloride brines. Concerning uranium precipitation, the reactivity of four potential reductants under conditions relevant for URU deposits genesis is investigated: H 2 , CH 4 , Fe(II) and the C-graphite. The kinetics of reduction reaction is measured as a function of temperature, salinity, pH and concentration of reductant. H 2 , CH 4 , and the C-graphite are very efficient while Fe(II) is not able to reduce U(VI) in same conditions. The duration of the mineralizing event is controlled by (i) the U concentration in the ore-forming fluids and (ii) by the generation of gaseous reductants, and not by the reduction kinetics. These mobile and efficient gaseous reductant could be at the origin of the extremely focus and massive character of ore in URU deposits. Finally, first partition coefficients uraninite/fluid of trace elements are obtained. This last part opens-up new perspectives on (i) REE signatures interpretation for a given type of uranium deposit (ii) and reconstruction of mineralizing fluids composition. (author) [fr

Atmospheric concentrations and deposition of oxidised sulfur and nitrogen species at Petaling Jaya, Malaysia, 1993-1998

Energy Technology Data Exchange (ETDEWEB)

Ayers, G.P.; Gillett, R.W.; Manins, P.C. [CSIRO Atmospheric Research, Aspendale, VIC (Australia); Peng Leong Chow; Fook Lim Sze [Malaysian Meteorological Service, Petaling Jaya (Malaysia); Kong Cheah Wai [Tenaga Nasional R and D Berhad, Kajang (Malaysia)

2000-02-01

Wet-only rainwater composition, acid-precursor gas mixing ratios and aerosol loading were determined from weekly-averaged samples at Petaling Jaya, Malaysia, over the five year period from March 1993 to March 1998. Annual deposition fluxes of acidic sulfur and nitrogen species estimated from these data show this site to be heavily impacted by acidic deposition, with total oxidised sulfur plus nitrogen deposition in the range 277-480 meq m{sup -2} yr{sup -1}. Average contributions were 56% as sulfur species, 44% as nitrogen species, with wet deposition in this region of high rainfall accounting for 67% of total deposition. Thus total acid deposition fluxes were equivalent to levels that provided motivation for emissions reduction programs in both Europe and North America. The possibility of adverse environmental effects in Malaysia caused by acid deposition therefore merits serious consideration and assessment.

4.3. Decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid. The influence of temperature on reaction process was studied. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on temperature ranges from 25 to 95 deg C was defined. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on process duration (5-60 minutes) was defined as well. The optimal conditions of decomposition of danburite concentrate by nitric acid were proposed.

Transport of acid forming emissions and potential effects of deposition in northeastern Alberta and northern Saskatchewan: a problem analysis

Energy Technology Data Exchange (ETDEWEB)

Shewchuk, S.R.; Abouguendia, Z.M.; Atton, F.M.; Dublin, J.; Godwin, R.C.; Holowaychuk, N.; Hopkinson, R.; Liaw, W.K.; Maybank, J.; Padbury, G.A.

1981-01-01

The purpose of this report is to study the potential effects of acid rain in northeastern Alberta and northern Saskatchewan. A problem analysis was conducted of the transport, transformations and deposition of emissions in this region. Studied are the atmospheric processes, geology and soils, natural vegetation, and the aquatic systems. At present, no environmental damage attributable to acidic deposition has been detected in this region. Field surveys in the region have detected no effects of industrial emissions on vegetation except within a few kilometers of industrial operations. The earliest effects of acid deposition tend to appear within aquatic systems. Ten recommendations based on these findings are discussed. 109 references, 22 figures, 10 tables.

Analysis of leachability for a sandstone uranium deposite with high acid consumption and sensitivities in Inner Mongolia

International Nuclear Information System (INIS)

Cheng Wei; Miao Aisheng; Li Jianhua; Zhou Lei; Chang Jingtao

2014-01-01

In-situ Leaching adaptability of a ground water oxidation zone type sandstone uranium deposit from Inner Mongolia is studied. The ore of the uranium deposit has high acid consumption and sensitivities in in-situ leaching. The leaching process with agent of CO_2 + O_2 and adjusting concentration of HCO_3"- can be suitable for the deposit. (authors)

Assessing atmospheric nitrogen deposition to natural and semi-natural ecosystems – experience from Danish studies using the DAMOS system

DEFF Research Database (Denmark)

Hertel, Ole; Geels, Camilla; Frohn, Lise

2013-01-01

and ammonium (reaction products of nitrogen oxides and ammonia), but also dry deposition of other reactive nitrogen compounds (mainly nitrogen oxides in the form of gas phase nitric acid and nitrogen dioxide). In Denmark's environmental management of the sensitive terrestrial ecosystems modelling tools...... are required that account for both the local and the long-range transported contributions. This motivated development of the Danish Ammonia MOdelling System (DAMOS) that has been successfully applied to the assessment of atmospheric nitrogen loadings to sensitive Danish ecosystems. We present here three...... different examples of such assessments. Our results show that ecosystems located in Western Denmark (Case 1) receive the highest loads of atmospheric nitrogen depositions which generally exceed the critical load. This part of the country has the highest livestock density. In the Eastern part of the country...

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M; Kitunen, V [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H [Helsinki Univ. (Finland). Dept. of Forest Ecology

1997-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M.; Kitunen, V. [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H. [Helsinki Univ. (Finland). Dept. of Forest Ecology

1996-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Influence of acidic atmospheric deposition on soil solution composition in the Daniel Boone National Forest, Kentucky, USA

Science.gov (United States)

C.D. Barton; A.D. Karathanasis; G. Chalfant

2002-01-01

Acid atmosperic depositoin may enter an environmental ecosystem in a variety of forms and pathways, but the most common components include sulfuric and nitric acids formed when rainwater interacts with sulfur (SO3) and nitrogen (NO3) emmissions. For many soils and watersheds sensitive to acid deposition, the predominant...

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B; Cabal, H; Garcia, C

1998-07-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km{sup 2} grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs.

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B.; Cabal, H.; Garcia, C. [CIEMAT. Madrid (Spain)

1998-12-31

Annual and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To de this, updated database with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5 x 5 km``2 grid which allow to assess the methodology used in Europe to obtain the maps of excedance over the critical loads of pollutants. (Author) 32 refs.

Assessment of undiscovered sandstone copper deposits of the Kodar-Udokan area, Russia: Chapter M in Global mineral resource assessment

Science.gov (United States)

Zientek, Michael L.; Chechetkin, Vladimir S.; Parks, Heather L.; Box, Stephen E.; Briggs, Deborah A.; Cossette, Pamela M.; Dolgopolova, Alla; Hayes, Timothy S.; Seltmann, Reimar; Syusyura, Boris; Taylor, Cliff D.; Wintzer, Niki E.

2014-01-01

Mineral resource assessments integrate and synthesize available information as a basis for estimating the location, quality, and quantity of undiscovered mineral resources. This probabilistic mineral resource assessment of undiscovered sandstone copper deposits within Paleoproterozoic metasedimentary rocks of the Kodar-Udokan area in Russia is a contribution to a global assessment led by the U.S. Geological Survey (USGS). The purposes of this study are to (1) delineate permissive areas (tracts) to indicate where undiscovered sandstone-hosted copper deposits may occur within 2 km of the surface, (2) provide a database of known sandstone copper deposits and significant prospects, (3) estimate numbers of undiscovered deposits within these permissive tracts at several levels of confidence, and (4) provide probabilistic estimates of amounts of copper (Cu) and mineralized rock that could be contained in undiscovered deposits within each tract. The workshop for the assessment, held in October 2009, used a three-part form of mineral resource assessment as described by Singer (1993) and Singer and Menzie (2010).

Acidic deposition: State of science and technology. Report 2. Atmospheric processes research and process model development. Final report

International Nuclear Information System (INIS)

Hicks, B.B.; Draxler, R.R.; Albritton, D.L.; Fehsenfeld, F.C.; Davidson, C.I.

1990-10-01

The document represents an attempt to put together, in one place, a summary of the present state of knowledge concerning those processes that affect air concentrations of acidic and acidifying pollutants, during their transport, from emission to deposition. It is not intended to be an all-encompassing review of the entire breadth of each of the contributing disciplines, but instead focuses on those areas where the state of science has improved over the last decade--the period of the National Acid Precipitation Assessment Program. The discussion is not limited to NAPAP activities, although it is clear that the products of NAPAP research are perhaps given greater attention than are the results obtained elsewhere. This bias is partially intentional, since it is the INTEGRATED ASSESSMENT that is currently being prepared by NAPAP that constitutes the 'client' for the material presented here. The integrated assessment pay attention to the North American situation alone, and hence the present work gives greatest attention to the North American case, but with awareness of the need to place this particular situation in the context of the rest of the world

Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes

NARCIS (Netherlands)

Grinsven, van J.J.M.

1988-01-01

Atmospheric deposition of SO _x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; Beier, Colin M.; Weathers, K.C.; McPherson, G.T.; Bishop, Daniel A.

2013-01-01

We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been documented. Sugar maple is a dominant canopy species in the Adirondack Mountain ecoregion, and it has a high demand for Ca. Trees in this region growing on soils with poor acid–base chemistry (low exchangeable Ca and % base saturation [BS]) that receive relatively high levels of atmospheric sulfur and nitrogen deposition exhibited a near absence of SM seedling regeneration and lower crown vigor compared with study plots with relatively high exchangeable Ca and BS and lower levels of acidic deposition. Basal area increment averaged over the 20th century was correlated (p < 0.1) with acid–base chemistry of the Oa, A, and upper B soil horizons. A lack of Adirondack SM regeneration, reduced canopy condition, and possibly decreased basal area growth over recent decades are associated with low concentrations of nutrient base cations in this region that has undergone soil Ca depletion from acidic deposition.

Long-term changes in soil and stream chemistry across an acid deposition gradient in the northeastern United States

Science.gov (United States)

Siemion, Jason; McHale, Michael; Lawrence, Gregory B.; Burns, Douglas A.; Antidormi, Michael

2018-01-01

Declines in acidic deposition across Europe and North America have led to decreases in surface water acidity and signs of chemical recovery of soils from acidification. To better understand the link between recovery of soils and surface waters, chemical trends in precipitation, soils, and streamwater were investigated in three watersheds representing a depositional gradient from high to low across the northeastern United States. Significant declines in concentrations of H+ (ranging from −1.2 to −2.74 microequivalents [μeq] L−1 yr−1), NO3− (ranging from −0.6 to −0.84 μeq L−1 yr−1), and SO42− (ranging from −0.95 to −2.13 μeq L−1 yr−1) were detected in precipitation in the three watersheds during the period 1999 to 2013. Soil chemistry in the A horizon of the watershed with the greatest decrease in deposition showed significant decreases in exchangeable Al and increases in exchangeable bases. Soil chemistry did not significantly improve during the study in the other watersheds, and base saturation in the Oa and upper B horizons significantly declined in the watershed with the smallest decrease in deposition. Streamwater SO42−concentrations significantly declined in all three streams (ranging from −2.01 to −2.87 μeq L−1 yr−1) and acid neutralizing capacity increased (ranging from 1.38 to 1.60 μeq L−1 yr−1) in the two streams with the greatest decreases in deposition. Recovery of soils has likely been limited by decades of acid deposition that have leached base cations from soils with base-poor parent material.

The development of an approach to assess critical loads of acidity for woodland habitats in Great Britain

Directory of Open Access Journals (Sweden)

S. J. Langan

2004-01-01

Full Text Available Alongside other countries that are signatories to the UNECE Convention Long Range Transboundary on Air Pollution, the UK is committed to reducing the impact of air pollution on the environment. To advise and guide this policy in relation to atmospheric emissions of sulphur and nitrogen, a critical load approach has been developed. To assess the potential impact of these pollutants on woodland habitats a steady state, simple mass balance model has been parameterised. For mineral soils, a Ca:Al ratio in soil solution has been used as the critical load indicator for potential damage. For peat and organic soils critical loads have been set according to a pH criterion. Together these approaches have been used with national datasets to examine the potential scale of acidification in woodland habitats across the UK. The results can be mapped to show the spatial variability in critical loads of the three principal woodland habitat types (managed coniferous, managed broadleaved/ mixed woodland and unmanaged woodland. The results suggest that there is a wide range of critical loads. The most sensitive (lowest critical loads are associated with managed coniferous followed by unmanaged woodland on peat soils. Calculations indicate that at steady state, acid deposition inputs reported for 1995–1997 result in a large proportion of all the woodland habitats identified receiving deposition loads in excess of their critical load; i.e. critical loads are exceeded. These are discussed in relation to future modelled depositions for 2010. Whilst significant widespread negative impacts of such deposition on UK woodland habitats have not been reported, the work serves to illustrate that if acid deposition inputs were maintained and projected emissions reductions not achieved, the long-term sustainability of large areas of woodland in the UK could be compromised. Keywords: critical loads, acid deposition, acidification, woodland, simple mass balance model

Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

Directory of Open Access Journals (Sweden)

Han-Seung Lee

2018-01-01

Full Text Available The corrosion characteristics of 304 stainless steel (SS and titanium (Ti coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS, revealed that as exposure periods to solution were increased, the polarization resistance (Rp decreased and the charge transfer resistance (Rct increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4- contaminated water solution, that is, pH 4. Scanning electron microscope (SEM results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

1.6. The kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Mirzoev, D.Kh.; Boboev, Kh.E.

2016-01-01

Present article of book is devoted to kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit. It was defined that with temperature increasing the extraction rate of Al_2O_3 and Fe_2O_3 increases. The dependence of extraction rate of Al_2O_3 and Fe_2O_3 on process duration at hydrochloric acid decomposition of argillite was studied. The activation energy of the process was defined.

Economic filters for evaluating porphyry copper deposit resource assessments using grade-tonnage deposit models, with examples from the U.S. Geological Survey global mineral resource assessment: Chapter H in Global mineral resource assessment

Science.gov (United States)

Robinson, Gilpin R.; Menzie, W. David

2012-01-01

An analysis of the amount and location of undiscovered mineral resources that are likely to be economically recoverable is important for assessing the long-term adequacy and availability of mineral supplies. This requires an economic evaluation of estimates of undiscovered resources generated by traditional resource assessments (Singer and Menzie, 2010). In this study, simplified engineering cost models were used to estimate the economic fraction of resources contained in undiscovered porphyry copper deposits, predicted in a global assessment of copper resources. The cost models of Camm (1991) were updated with a cost index to reflect increases in mining and milling costs since 1989. The updated cost models were used to perform an economic analysis of undiscovered resources estimated in porphyry copper deposits in six tracts located in North America. The assessment estimated undiscovered porphyry copper deposits within 1 kilometer of the land surface in three depth intervals.

Hatching success in salamanders and chorus frogs at two sites in Colorado, USA: Effects of acidic deposition and climate

Science.gov (United States)

Muths, E.; Campbell, D.H.; Corn, P.S.

2003-01-01

The snowpack in the vicinity of the Mount Zirkel Wilderness Area is among the most acidic in the western United States. We analyzed water chemistry and examined hatching success in tiger salamanders and chorus frogs at ponds there and at nearby Rabbit Ears Pass (Dumont) to determine whether acid deposition affects amphibians or their breeding habitats at these potentially sensitive locations. We found a wide range of acid neutralizing capacity among ponds within sites; the minimum pH recorded during the experiment was 5.4 at one of 12 ponds with all others at pH ??? 5.7. At Dumont, hatching success for chorus frogs was greater in ponds with low acid neutralizing capacity; however, lowest pHs were >5.8. At current levels of acid deposition, weather and pond characteristics are likely more important than acidity in influencing hatching success in amphibian larvae at these sites.

Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

International Nuclear Information System (INIS)

Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

2013-01-01

Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

International Nuclear Information System (INIS)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E.

1995-01-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E. [Manchester Metropolitan University, Manchester (United Kingdom). Dept. of Environmental and Geographical Sciences

1995-12-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs.

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA.

Science.gov (United States)

McHale, Michael R; Burns, Douglas A; Siemion, Jason; Antidormi, Michael R

2017-10-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO 4 2- ) concentrations (mean trend of -2.5 μeq L -1 yr -1 ); hydrogen ion (H + ) and inorganic monomeric aluminum (Al im ) also decreased significantly (mean trends of -0.3 μeq L -1 yr -1 for H + and -0.1 μeq L -1 yr -1 for Al im for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L -1 yr -1 for all 5 sites, which was 4 fold less than the decrease in SO 4 2- concentrations. These upward trends in ANC were limited by coincident decreases in base cations (-1.3 μeq L -1 yr -1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO 3 - ) concentrations despite significant decreasing trends in NO 3 - wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (-0.2 μeq L -1 yr -1 ) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations. Published by Elsevier Ltd.

Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

Science.gov (United States)

Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

2014-01-01

Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

Determination of soluble ultra-trace metals and metalloids in rainwater and atmospheric deposition fluxes: a 2-year survey and assessment.

Science.gov (United States)

Montoya-Mayor, R; Fernández-Espinosa, A J; Seijo-Delgado, I; Ternero-Rodríguez, M

2013-08-01

The present work investigates the relationships between composition of rainwater and dry deposition fluxes by trace metals and metalloids. A modification in automatic "wet-only" and "dry-only" samplers was applied, which allowed the collection and conservation of samples separately. ICP-MS technique was used for the determination of analytes in samples. Concentrations of soluble elements in rainwater were measured directly in filtered samples. A sequential acid treatment with nitric, hydrofluoric and finally perchloric acids was used to measure the total contents of metals and metalloids in coarse particles. Variation between periods of heavy and light rains was assessed. Almost all of the metals and metalloids - B, Tl, Th, U, Al, Cs, Be, Ti and others - studied in dry deposition showed important decreases in concentrations (40-92%) during periods of heavy rainfall. Most of these metals and metalloids - As, Cr, Co, Ni - presented their highest levels (53-90%) in heavy rainfall periods in rainwater samples. Sources were identified in both types of samples collected using a new chemometric tool (SPCA). Urban traffic, surrounding contaminated soils and local anthropogenic sources were identified for rainwater samples. Natural and contaminated soils and general anthropogenic emissions were the sources identified for dry deposition fluxes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

DEFF Research Database (Denmark)

Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

2016-01-01

The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

Science.gov (United States)

Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

2009-01-01

Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA

Science.gov (United States)

McHale, Michael; Burns, Douglas A.; Siemion, Jason; Antidormi, Michael

2017-01-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42−concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

Hexanoic Acid Treatment Prevents Systemic MNSV Movement in Cucumis melo Plants by Priming Callose Deposition Correlating SA and OPDA Accumulation

Directory of Open Access Journals (Sweden)

Emma Fernández-Crespo

2017-10-01

Full Text Available Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV and demonstrated the efficacy of hexanoic acid (Hx priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and hexanoic acid-induced resistance (Hx-IR to MNSV. Our data indicate important roles of salicylic acid (SA, 12-oxo-phytodienoic acid (OPDA, jasmonic-isoleucine, and ferulic acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.

Effects of acid deposition on tree roots

Energy Technology Data Exchange (ETDEWEB)

Persson, H. [Swedish Univ. of Agricultural Sciences (Sweden). Dept. of Ecology and Environmental Research

1995-12-31

Large forest regions in SW Sweden have been exposed to high levels of acid deposition for many decades, causing soil acidification in forest soils. Historically, SO{sub 2} has been the major acidification agent, but lately nitrogen compounds increasingly have become important. The amount and chemical form of nitrogen strongly affects the pH in the rhizosphere and rhizoplane. Many forest stands show a positive growth response to increased nitrogen input, even in heavily N-loaded areas. Nitrogen fertilization experiments suggest that part of the increased forest production is caused by a translocation of biomass production from below-ground to above-ground parts. At the same time fine-root growth dynamics are strongly affected by the high N supply. Deficiencies of various nutrients (Mg,Ca,K,Mn and Zn) obtained from needle analyses have been reported from different Picea abies stands. In areas with more extensive acidification and nutrient leaching, a decline in tree vitality has been observed. Although deficiency symptoms in forest trees may be reflected in nitrogen/cation ratios in fine roots, few attempts have been made to explain forest damage symptoms from fine-root chemistry. Root damage is often described as a decline in the amount of living fine roots, an increase in the amount of dead versus live fine roots (a lower live/dead ratio) and an increasing amount of dead medium and coarse roots. The primary objectives of the present presentation were to analyse available data on the effects of high nitrogen and sulphur deposition on mineral nutrient balance in tree fine roots and to evaluate the risk of Al interference with cation uptake by roots

Effects of acid deposition on tree roots

Energy Technology Data Exchange (ETDEWEB)

Persson, H [Swedish Univ. of Agricultural Sciences (Sweden). Dept. of Ecology and Environmental Research

1996-12-31

Large forest regions in SW Sweden have been exposed to high levels of acid deposition for many decades, causing soil acidification in forest soils. Historically, SO{sub 2} has been the major acidification agent, but lately nitrogen compounds increasingly have become important. The amount and chemical form of nitrogen strongly affects the pH in the rhizosphere and rhizoplane. Many forest stands show a positive growth response to increased nitrogen input, even in heavily N-loaded areas. Nitrogen fertilization experiments suggest that part of the increased forest production is caused by a translocation of biomass production from below-ground to above-ground parts. At the same time fine-root growth dynamics are strongly affected by the high N supply. Deficiencies of various nutrients (Mg,Ca,K,Mn and Zn) obtained from needle analyses have been reported from different Picea abies stands. In areas with more extensive acidification and nutrient leaching, a decline in tree vitality has been observed. Although deficiency symptoms in forest trees may be reflected in nitrogen/cation ratios in fine roots, few attempts have been made to explain forest damage symptoms from fine-root chemistry. Root damage is often described as a decline in the amount of living fine roots, an increase in the amount of dead versus live fine roots (a lower live/dead ratio) and an increasing amount of dead medium and coarse roots. The primary objectives of the present presentation were to analyse available data on the effects of high nitrogen and sulphur deposition on mineral nutrient balance in tree fine roots and to evaluate the risk of Al interference with cation uptake by roots

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystem

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.A.R.; Heck, I.C.C; Hesen, P.L.G.M.; Leuven, R.S.E.W.; Roelofs, J.G.M.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH 3.8. Under acidified conditions, ammonium sulphate deposition led to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr, the acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 references.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.; Heck, I.C.; Hesen, P.L.; Leuven, R.S.; Roelofs, J.G.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulfate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulfate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulfate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH = 3.8. Under acidified conditions, ammonium sulfate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulfate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulfate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 refs.

Gasification of carbon deposits on catalysts and metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Figueiredo, J L

1986-10-01

'Coke' deposited on catalysts and reactor surfaces includes a variety of carbons of different structures and origins, their reactivities being conveniently assessed by Temperature Programmed Reaction (TPR). The gasification of carbon deposits obtained in the laboratory under well controlled conditions, and the regeneration of coked catalysts from petroleum refining processes are reviewed and discussed. Filamentary carbon deposits, containing dispersed metal particles, behave as supported metal catalysts during gasification, and show high reactivities. Pyrolytic and acid catalysis carbons are less reactive on their own, as the gasification is not catalysed; however, metal components of the catalyst or metal impurities deposited on the surface may enhance gasification. 26 refs., 8 figs., 2 tabs.

Polymer deposition morphology by electrospray deposition - Modifications through distance variation

International Nuclear Information System (INIS)

Altmann, K.; Schulze, R.-D.; Friedrich, J.

2014-01-01

Electrospray deposition (ESD) of highly diluted polymers was examined with regard to the deposited surface structure. Only the flight distance (flight time) onto the resulting deposited surface was varied from 20 to 200 mm. An apparatus without any additional heating or gas flows was used. Polyacrylic acid (PAA) and polyallylamine (PAAm) in methanol were deposited on Si wafers. The polymer layers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, derivatization reactions and Fourier transform infrared spectroscopy using a grazing incidence unit. SEM images illustrated the changing structures of PAA and PAAm. For PAA the deposited structure changed from a smooth film (20 mm) to a film with individual droplets on the coated surface (100 mm and 200 mm), while for PAAm individual droplets can be seen at all distances. The ESD process with cascades of splitting droplets slows down for PAA after distances greater than 40 mm. In contrast, the ESD process for PAAm is nearly stopped within the first flight distance of 20 mm. Residual solvent analysis showed that most of the solvent evaporated within the first 20 mm capillary-sample distance. - Highlights: • We deposited polyacrylic acid and polyallylamine by electrospray ionization (ESI). • The morphology in dependence of flight distance (20 mm to 200 mm) was analyzed. • The amount of residual solvent after deposition was determined. • ESI-process slows down for polyacrylic acid after 40 mm flight distance. • ESI-Process is complete for polyallylamine within the first 20 mm

The effect of pomegranate seed oil and grapeseed oil on cis-9, trans-11 CLA (rumenic acid), n-3 and n-6 fatty acids deposition in selected tissues of chickens.

Science.gov (United States)

Białek, A; Białek, M; Lepionka, T; Kaszperuk, K; Banaszkiewicz, T; Tokarz, A

2018-04-23

The aim of this study was to determine whether diet modification with different doses of grapeseed oil or pomegranate seed oil will improve the nutritive value of poultry meat in terms of n-3 and n-6 fatty acids, as well as rumenic acid (cis-9, trans-11 conjugated linoleic acid) content in tissues diversified in lipid composition and roles in lipid metabolism. To evaluate the influence of applied diet modification comprehensively, two chemometric methods were used. Results of cluster analysis demonstrated that pomegranate seed oil modifies fatty acids profile in the most potent way, mainly by an increase in rumenic acid content. Principal component analysis showed that regardless of type of tissue first principal component is strongly associated with type of deposited fatty acid, while second principal component enables identification of place of deposition-type of tissue. Pomegranate seed oil seems to be a valuable feed additive in chickens' feeding. © 2018 Blackwell Verlag GmbH.

Maternal Docosahexaenoic Acid Increases Adiponectin and Normalizes IUGR-Induced Changes in Rat Adipose Deposition

Directory of Open Access Journals (Sweden)

Heidi N. Bagley

2013-01-01

Full Text Available Intrauterine growth restriction (IUGR predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor-γ2 (PPARγ2 in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPARγ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA, a PPARγ agonist, would normalize IUGR adipose deposition in association with increased PPARγ, adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI- induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1 normalizes IUGR-induced changes in adipose deposition and visceral PPARγ expression in male rats and (2 increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Maternal docosahexaenoic acid increases adiponectin and normalizes IUGR-induced changes in rat adipose deposition.

Science.gov (United States)

Bagley, Heidi N; Wang, Yan; Campbell, Michael S; Yu, Xing; Lane, Robert H; Joss-Moore, Lisa A

2013-01-01

Intrauterine growth restriction (IUGR) predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor- γ 2 (PPAR γ 2) in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPAR γ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA), a PPAR γ agonist, would normalize IUGR adipose deposition in association with increased PPAR γ , adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI-) induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1) normalizes IUGR-induced changes in adipose deposition and visceral PPAR γ expression in male rats and (2) increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Experimental skin deposition of chromium on the hands following handling of samples of leather and metal

DEFF Research Database (Denmark)

Bregnbak, David; Thyssen, Jacob P.; Jellesen, Morten Stendahl

2016-01-01

Background: Chromium is an important skin sensitizer. Exposure to it has been regulated in cement, and recently in leather. Studies on the deposition of chromium ions on the skin as a result of handling different chromium-containing materials are sparse, but could improve the risk assessment...... of contact sensitization and allergic contact dermatitis caused by chromium. Objectives: To determine whether the handling of chromium-containing samples of leather and metal results in the deposition of chromium onto the skin. Methods: Five healthy volunteers participated. For 30 min, they handled samples...... of leather and metal known to contain and release chromium. Skin deposition of chromium was assessed with the acid wipe sampling technique. Results: Acid wipe sampling of the participants' fingers showed chromium deposition on the skin in all participants who had been exposed to leather (range 0.01–0.20 µg...

Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO2 and reduced acid deposition.

Science.gov (United States)

Levesque, Mathieu; Andreu-Hayles, Laia; Pederson, Neil

2017-04-10

Dynamic global vegetation models (DGVM) exhibit high uncertainty about how climate change, elevated atmospheric CO 2 (atm. CO 2 ) concentration, and atmospheric pollutants will impact carbon sequestration in forested ecosystems. Although the individual roles of these environmental factors on tree growth are understood, analyses examining their simultaneous effects are lacking. We used tree-ring isotopic data and structural equation modeling to examine the concurrent and interacting effects of water availability, atm. CO 2 concentration, and SO 4 and nitrogen deposition on two broadleaf tree species in a temperate mesic forest in the northeastern US. Water availability was the strongest driver of gas exchange and tree growth. Wetter conditions since the 1980s have enhanced stomatal conductance, photosynthetic assimilation rates and, to a lesser extent, tree radial growth. Increased water availability seemingly overrides responses to reduced acid deposition, CO 2 fertilization, and nitrogen deposition. Our results indicate that water availability as a driver of ecosystem productivity in mesic temperate forests is not adequately represented in DGVMs, while CO 2 fertilization is likely overrepresented. This study emphasizes the importance to simultaneously consider interacting climatic and biogeochemical drivers when assessing forest responses to global environmental changes.

Stability of sputter deposited ZnO:Cr films against acids

International Nuclear Information System (INIS)

Shinoda, Makoto; Nishide, Toshikazu; Sawada, Yutaka; Hosaka, Masato; Matsumoto, Toshihiko.

1993-01-01

ZnO:Cr films were deposited on water-cooled soda-lime glass substrates at room temperature in an Ar atmosphere by rf magnetron sputtering of a ZnO target on which Cr chips were placed. The films exhibited extraordinary stability against acids such as HCl or HNO 3 , and also high resistivities similar to those of ZnO films. The addition of Cr suppressed the growth of ZnO grains which resulted in the formation of a dense film with a smooth surface. The stability and high resistivity displayed by the ZnO:Cr films can be attributed to the formation of a chromium-oxide-rich grain boundary. (author)

Zinc deposition and dissolution in methanesulfonic acid onto a carbon composite electrode as the negative electrode reactions in a hybrid redox flow battery

International Nuclear Information System (INIS)

Leung, P.K.; Ponce-de-Leon, C.; Low, C.T.J.; Walsh, F.C.

2011-01-01

Highlights: → Use methanesulfonic acid to avoid dendrite formation during a long (>4 h) zinc electrodeposition. → Electrochemical characterization of Zn(II) deposition and its morphology using methanesulfonic acid solutions. → Use of additives to improve the efficiency of zinc deposition and dissolution as the half cell reaction of a redox flow battery. - Abstract: Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn 2+ ions was 7.5 x 10 -6 cm 2 s -1 . The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn 2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 x 10 -3 mol dm -3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm -2 .

4.2. The kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit. The dependence of nitric acid decomposition of calcined boric raw material for extraction of boron oxide on temperature (20-100 deg C) and process duration (15-60 minutes) was defined. It was defined that at temperature increasing the extraction rate of boron oxide increases from 20.8 to 78.6%.

Dendrochemical evidence for soil recovery from acidic deposition in forests of the northeastern U.S. with comparisons to the southeastern U.S. and Russia

Science.gov (United States)

Walter C. Shortle; Kevin T. Smith; Andrei G. Lapenis

2017-01-01

A soil resampling approach has detected an early stage of recovery in the cation chemistry of spruce forest soil due to reductions in acid deposition. That approach is limited by the lack of soil data and archived soil samples prior to major increases in acid deposition during the latter half of the 20th century. An alternative approach is the dendrochemical analysis...

Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells

Energy Technology Data Exchange (ETDEWEB)

Tavakoli, M.M. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Simchi, A., E-mail: simchi@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Aashuri, H. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of)

2015-04-15

Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction, absorption and dynamic light scattering showed that the nanocrystals processed at the supercritical condition (330 °C) are fully crystalline with a narrow size distribution of ∼3 nm with an absorption wavelength of 915 nm (bandgap of 1.3 eV). Fourier transform infrared spectroscopy indicated that the PbS quantum dots are passivated by oleic acid molecules during the growth. Photovoltaic characteristics of Schottky junction solar cells showed an improvement over devices prepared by spin-coating. - Highlights: • Supercritical fluid processing and in situ deposition of PbS QDs are presented. • The prepared nanocrystals are mono-dispersed with an optical bandgap of 1.3 eV. • Photovoltaic performance of the in situ deposited nanocrystals is reported. • An improved PV performance compared to spin coated Schottky solar cells is shown.

An investigation for the economic assessment of uranium deposits and mining projects

International Nuclear Information System (INIS)

Alnajim, N.

1980-01-01

It is the aim of this thesis to supply a comprehensive basis for decisions to be made in connection with the detection, exploration, extraction processing and marketing of uranium. The deposit types and forms, the technologies of exploration, extraction and processing as well as the most economic procedure for the exploitation of such deposits are presented in detail. This results in an assessment system which serves to consider the necessity for the construction of uranium ore deposits. (orig./HP) [de

Quantitative Assessment of Spray Deposition with Water-Sensitive Paper

Science.gov (United States)

Spray droplets, discharged from the lower six nozzles of an airblast sprayer, were sampled on pairs of absorbent filter and water-sensitive papers at nine distances from sprayer. Spray deposition on filter targets were measured by fluorometry and spray distribution on WSP targets were assessed by t...

Definition and Reliability Assessment of Elementary Ultrasonographic Findings in Calcium Pyrophosphate Deposition Disease

DEFF Research Database (Denmark)

Filippou, Georgios; Scirè, Carlo A; Damjanov, Nemanja

2017-01-01

OBJECTIVE: To define the ultrasonographic characteristics of calcium pyrophosphate crystal (CPP) deposits in joints and periarticular tissues and to evaluate the intra- and interobserver reliability of expert ultrasonographers in the assessment of CPP deposition disease (CPPD) according to the ne...

Metallization on FDM Parts Using the Chemical Deposition Technique

Directory of Open Access Journals (Sweden)

Azhar Equbal

2014-08-01

Full Text Available Metallization of ABS (acrylonitrile-butadiene-styrene parts has been studied on flat part surfaces. These parts are fabricated on an FDM (fused deposition modeling machine using the layer-wise deposition principle using ABS as a part material. Electroless copper deposition on ABS parts was performed using two different surface preparation processes, namely ABS parts prepared using chromic acid for etching and ABS parts prepared using a solution mixture of sulphuric acid and hydrogen peroxide (H2SO4/H2O2 for etching. After surface preparations using these routes, copper (Cu is deposited electrolessly using four different acidic baths. The acidic baths used are 5 wt% CuSO4 (copper sulfate with 15 wt% of individual acids, namely HF (hydrofluoric acid, H2SO4 (sulphuric acid, H3PO4 (phosphoric acid and CH3COOH (acetic acid. Cu deposition under different acidic baths used for both the routes is presented and compared based on their electrical performance, scanning electron microscopy (SEM and energy dispersive X-ray spectrometry (EDS. The result shows that chromic acid etched samples show better electrical performance and Cu deposition in comparison to samples etched via H2SO4/H2O2.

The importance of variations in the deposition velocity assumed for the assessment of airborne radionuclide releases

International Nuclear Information System (INIS)

Miller, C.W.; Hoffman, F.O.; Shaeffer, D.L.

1978-01-01

In environmental radiological assessments, the depletion of airborne plumes by dry deposition processes and the subsequent contamination of ground and vegetation have been estimated through the use of a parameter termed the 'deposition velocity'. The sensitivity of environmental assessment models to changes in values of deposition velocity is here examined so that the effect of potential variations of deposition velocity on calculations of radiation dose can be determined. The results show that until more data are available great care must be exercised when applying theoretical ideas and scientific judgement in the selection of a value of the deposition velocity to be used in calculating the dose to man as a result of deposition. (U.K.)

Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

Science.gov (United States)

Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

2017-06-01

Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

Target loads of atmospheric sulfur deposition for the protection and recovery of acid-sensitive streams in the Southern Blue Ridge Province.

Science.gov (United States)

Sullivan, Timothy J; Cosby, Bernard J; Jackson, William A

2011-11-01

An important tool in the evaluation of acidification damage to aquatic and terrestrial ecosystems is the critical load (CL), which represents the steady-state level of acidic deposition below which ecological damage would not be expected to occur, according to current scientific understanding. A deposition load intended to be protective of a specified resource condition at a particular point in time is generally called a target load (TL). The CL or TL for protection of aquatic biota is generally based on maintaining surface water acid neutralizing capacity (ANC) at an acceptable level. This study included calibration and application of the watershed model MAGIC (Model of Acidification of Groundwater in Catchments) to estimate the target sulfur (S) deposition load for the protection of aquatic resources at several future points in time in 66 generally acid-sensitive watersheds in the southern Blue Ridge province of North Carolina and two adjoining states. Potential future change in nitrogen leaching is not considered. Estimated TLs for S deposition ranged from zero (ecological objective not attainable by the specified point in time) to values many times greater than current S deposition depending on the selected site, ANC endpoint, and evaluation year. For some sites, one or more of the selected target ANC critical levels (0, 20, 50, 100μeq/L) could not be achieved by the year 2100 even if S deposition was reduced to zero and maintained at that level throughout the simulation. Many of these highly sensitive streams were simulated by the model to have had preindustrial ANC below some of these target values. For other sites, the watershed soils contained sufficiently large buffering capacity that even very high sustained levels of atmospheric S deposition would not reduce stream ANC below common damage thresholds. Copyright © 2011 Elsevier Ltd. All rights reserved.

Nitrogen deposition and grass encroachment in calcareous and acidic Grey dunes (H2130) in NW-Europe

NARCIS (Netherlands)

Kooijman, A.M.; van Til, M.; Noordijk, E.; Remke, E.; Kalbitz, K.

We present an overview of high nitrogen deposition effects on coastal dune grasslands in NW-Europe (H2130), especially concerning grass encroachment in calcareous and acidic Grey Dunes. The problem is larger than previously assumed, because critical loads are still too high, and extra N-input from

Volcanogenic Uranium Deposits: Geology, Geochemical Processes, and Criteria for Resource Assessment

Science.gov (United States)

Nash, J. Thomas

2010-01-01

Felsic volcanic rocks have long been considered a primary source of uranium for many kinds of uranium deposits, but volcanogenic uranium deposits themselves have generally not been important resources. Until the past few years, resource summaries for the United States or the world generally include volcanogenic in the broad category of 'other deposits' because they comprised less than 0.5 percent of past production or estimated resources. Exploration in the United States from the 1940s through 1982 discovered hundreds of prospects in volcanic rocks, of which fewer than 20 had some recorded production. Intensive exploration in the late 1970s found some large deposits, but low grades (less than about 0.10 percent U3O8) discouraged economic development. A few deposits in the world, drilled in the 1980s and 1990s, are now known to contain large resources (>20,000 tonnes U3O8). However, research on ore-forming processes and exploration for volcanogenic deposits has lagged behind other kinds of uranium deposits and has not utilized advances in understanding of geology, geochemistry, and paleohydrology of ore deposits in general and epithermal deposits in particular. This review outlines new ways to explore and assess for volcanogenic deposits, using new concepts of convection, fluid mixing, and high heat flow to mobilize uranium from volcanic source rocks and form deposits that are postulated to be large. Much can also be learned from studies of epithermal metal deposits, such as the important roles of extensional tectonics, bimodal volcanism, and fracture-flow systems related to resurgent calderas. Regional resource assessment is helped by genetic concepts, but hampered by limited information on frontier areas and undiscovered districts. Diagnostic data used to define ore deposit genesis, such as stable isotopic data, are rarely available for frontier areas. A volcanic environment classification, with three classes (proximal, distal, and pre-volcanic structures

Assessment of risks of loose landslide deposits formed by the 2008 Wenchuan earthquake

Science.gov (United States)

Zhang, S.; Zhang, L. M.; Peng, M.; Zhang, L. L.; Zhao, H. F.; Chen, H. X.

2012-05-01

A Geographic Information System (GIS)-based quantitative risk assessment methodology was adopted to evaluate the risks of loose deposits formed by the 2008 Wenchuan earthquake along a highway near the epicenter. A total of 305 loose deposits with a total volume of 4.0 × 107 m3 has been identified. A physical model was used to determine the failure probability of these loose deposits under six rainfall scenarios, assuming the loose deposits as infinite slopes. The calculated probability of rain-induced slope failures is verified by the recorded landslides at the same site during a storm in 2010. Seventy-nine out of the 112 rain-induced loose deposit failures are predicted by the reliability analysis, with an accuracy of 71%. The results of reliability analysis and information on the consequence of these rain-induced landslides enable the estimation of the annual societal and individual risks of the loose deposits. Under the rainfall scenarios of 30 mm/12 h and 70 mm/12 h, the estimated annual societal risks reach 8.8 and 7.5, respectively, and the individual risks reach 0.05 and 0.04, respectively, which are very high compared with present risk acceptance criteria. The preliminary assessment provides a benchmark for studying the long-term risks of these loose deposits and engineering decision.

Application of a complex transport problem for simulating an acid rain episode in Europe. Anwendung eines komplexen Ausbreitungsmodells zur Simulation einer Episode saurer Deposition ueber Europa

Energy Technology Data Exchange (ETDEWEB)

Stern, R; Scherer, B

1989-04-01

For the first time in Europe, a comprehensive Eulerian regional tropospheric transport, transformation and removal model has been applied to an european wide acid deposition episode. This model, the Transport And Deposition of Acidifying Pollutants (TADAP) model incorporated detailed knowledge of the relevant physicochemical processes which lead to the formation of photochemical oxidants and acidifying pollutants. The EUROPA-model (EUM) of the German Weather Service, a limited area numerical weather prediction model, has been used to derive the total meteorological cloud variables. The application of the EUM/TADAP-modelling system to a 20 day-wintertime acid deposition episode in Europe showed that it is possible to model the principal features of the acid deposition system. In general, there is reasonable agreement between observed and predicted concentration and deposition patterns. Most discrepancies from observed trends can be explained by deviations between the modelled and the actual meteorology. First sensitivity studies with TADAP directed to reveal the influence of emission changes on the acid deposition system showed that there are considerable non-proportionalities between depositions of secondary pollutants and the emissions of the respective precursors. The nonlinearities arise due to the chemical coupling of the SO{sub x}/No{sub x}/VOC-system. This makes the design of control strategies to a highly complex task. Strategies developed to tackle different air pollution problems can therefore not be looked upon independently. (orig.) With 47 refs., 42 figs.

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

Science.gov (United States)

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

Directory of Open Access Journals (Sweden)

Rachela G. Milazzo

2017-01-01

Full Text Available The morphology of gold nanoparticles (AuNPs deposited on a (100 silicon wafer by simple immersion in a solution containing a metal salt and hydrofluoric acid (HF is altered by HF treatment both before and after deposition. The gold clusters are characterized by the presence of flat regions and quasispherical particles consistent with the layer-by-layer or island growth modes, respectively. The cleaning procedure, including HF immersion prior to deposition, affects the predominantly occurring gold structures. Flat regions, which are of a few tens of nanometers long, are present after immersion for 10 s. The three-dimensional (3D clusters are formed after a cleaning procedure of 4 min, which results in a large amount of spherical particles with a diameter of ≈15 nm and in a small percentage of residual square layers of a few nanometers in length. The samples were also treated with HF after the deposition and we found out a general thickening of flat regions, as revealed by TEM and AFM analysis. This result is in contrast to the coalescence observed in similar experiments performed with Ag. It is suggested that the HF dissolves the silicon oxide layer formed on top of the thin flat clusters and promotes the partial atomic rearrangement of the layered gold atoms, driven by a reduction of the surface energy. The X-ray diffraction investigation indicated changes in the crystalline orientation of the flat regions, which partially lose their initially heteroepitaxial relationship with the substrate. A postdeposition HF treatment for almost 70 s has nearly the same effect of long duration, high temperature annealing. The process presented herein could be beneficial to change the spectral response of nanoparticle arrays and to improve the conversion efficiency of hybrid photovoltaic devices.

Modelling regional response of lakewater chemistry to changes in acidic deposition: the MAGIC model applied to lake surveys in southernmost Norway 1974-1986-1995

Directory of Open Access Journals (Sweden)

B. J. Cosby

1998-01-01

Full Text Available Two methods for modelling regional responses of lake water quality to changes in acidic deposition in southernmost Norway were examined. Both methods are based upon the MAGIC model but differ in mode of regional application; one uses site-specific while the other uses Monte-Carlo methods for model calibration. The simulations of regional responses from both methods were compared with observed responses based on data from three lake surveys in southernmost Norway conducted in 1974, 1986 and 1995. The regional responses of the two modelling approaches were quite similar and agreed well with the observed regional distributions of lakewater chemistry variables. From 1974 to 1986 the observed data indicated that despite a decline of approximately 10% in sulphate (SO4 deposition, the mean acid neutralizing capacity (ANC of lakes in southernmost Norway declined by approximately 6 μeq l-1. Both modelling approaches simulated no change or a very small decline in mean ANC for that period. From 1986 to 1995 the observed data indicated that, in response to an approximate 40% decline in SO4 deposition, the mean ANC of lakes in southernmost Norway increased by 11-16 μeq l-1. The modelling approaches simulated increases of 9-10 μeq l-1 in mean ANC for the same period. Both simulations and observations indicate that > 65% of lakes in southernmost Norway were acidic in 1974 and 1995. Both simulation methods predict that >65% of the lakes in southernmost Norway will have positive ANC values within 10 years of reductions of SO4 deposition to 20% of 1974 levels. Of the two regionalization methods the site-specific method appears preferable, because whereas the Monte-Carlo method gives results for a region as a whole, the site-specific method also reveals patterns within the region. The maintenance of a one-to-one correspondence between simulated and observed systems means that simulation results can be mapped for a geographically explicit presentation of model

Effects of multiple stresses hydropower, acid deposition and climate change on water chemistry and salmon populations in the River Otra, Norway.

Science.gov (United States)

Wright, Richard F; Couture, Raoul-Marie; Christiansen, Anne B; Guerrero, José-Luis; Kaste, Øyvind; Barlaup, Bjørn T

2017-01-01

Many surface waters in Europe suffer from the adverse effects of multiple stresses. The Otra River, southernmost Norway, is impacted by acid deposition, hydropower development and increasingly by climate change. The river holds a unique population of land-locked salmon and anadromous salmon in the lower reaches. Both populations have been severely affected by acidification. The decrease in acid deposition since the 1980s has led to partial recovery of both populations. Climate change with higher temperatures and altered precipitation can potentially further impact fish populations. We used a linked set of process-oriented models to simulate future climate, discharge, and water chemistry at five sub-catchments in the Otra river basin. Projections to year 2100 indicate that future climate change will give a small but measureable improvement in water quality, but that additional reductions in acid deposition are needed to promote full restoration of the fish communities. These results can help guide management decisions to sustain key salmon habitats and carry out effective long-term mitigation strategies such as liming. The Otra River is typical of many rivers in Europe in that it fails to achieve the good ecological status target of the EU Water Framework Directive. The programme of measures needed in the river basin management plan necessarily must consider the multiple stressors of acid deposition, hydropower, and climate change. This is difficult, however, as the synergistic and antagonistic effects are complex and challenging to address with modelling tools currently available. Copyright © 2016 Elsevier B.V. All rights reserved.

Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

Science.gov (United States)

Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

2015-04-01

Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

Environmental and geochemical assessment of surface sediments on irshansk ilmenite deposit area

Directory of Open Access Journals (Sweden)

Наталия Олеговна Крюченко

2015-03-01

Full Text Available It is revealed the problem of pollution of surface sediments of Irshansk ilmenite deposit area of various chemical elements hazard class (Mn, V, Ba, Ni, Co, Cr, Mo, Cu, Pb, Zn. It is determined its average content in surface sediments of various functional areas (forest and agricultural land, flood deposits, reclaimed land, calculated geochemical criteria, so given ecological and geochemical assessment of area

Target loads of atmospheric sulfur deposition for the protection and recovery of acid-sensitive streams in the Southern Blue Ridge Province

Science.gov (United States)

Timothy Sullivan; Bernard Cosby; William Jackson

2011-01-01

An important tool in the evaluation of acidification damage to aquatic and terrestrial ecosystems is the critical load (CL), which represents the steady-state level of acidic deposition below which ecological damage would not be expected to occur, according to current scientific understanding. A deposition load intended to be protective of a specified resource...

Effects of atmospheric deposition of energy-related pollutants on water quality: a review and assessment

International Nuclear Information System (INIS)

Davis, M.J.

1981-05-01

The effects on surface-water quality of atmospheric pollutants that are generated during energy production are reviewed and evaluated. Atmospheric inputs from such sources to the aquatic environment may include trace elements, organic compounds, radionuclides, and acids. Combustion is the largest energy-related source of trace-element emissions to the atmosphere. This report reviews the nature of these emissions from coal-fired power plants and discusses their terrestrial and aquatic effects following deposition. Several simple models for lakes and streams are developed and are applied to assess the potential for adverse effects on surface-water quality of trace-element emissions from coal combustion. The probability of acute impacts on the aquatic environment appears to be low; however, more subtle, chronic effects are possible. The character of acid precipitation is reviewed, with emphasis on aquatic effects, and the nature of existing or potential effects on water quality, aquatic biota, and water supply is considered. The response of the aquatic environment to acid precipitation depends on the type of soils and bedrock in a watershed and the chemical characteristics of the water bodies in question. Methods for identifying regions sensitive to acid inputs are reviewed. The observed impact of acid precipitation ranges from no effects to elimination of fish populations. Coal-fired power plants and various stages of the nuclear fuel cycle release radionuclides to the atmosphere. Radioactive releases to the atmosphere from these sources and the possible aquatic effects of such releases are examined. For the nuclear fuel cycle, the major releases are from reactors and reprocessing. Although aquatic effects of atmospheric releases have not been fully quantified, there seems little reason for concern for man or aquatic biota

Essential application of depositional analysis and interpretation in hydrogeologic assessments of contaminated sites

International Nuclear Information System (INIS)

Sciacca, J.

1991-01-01

In most hydrogeologic studies of contaminated sites, little attention is given to analysis of depositional environments and associated depositional patterns. This analysis is essential for sedimentary deposits present at a majority of these sites. The depositional processes associated with alluvial, fluvial and deltaic environments yield heterogeneity ranging from large to small scale. These processes also yield preferential grain orientations in coarse grained units which result in preferential directions of increased permeability. Studies conducted in fluvial and deltaic petroleum reservoirs have shown varying permeabilities resulting from deposition that strongly control the flow of fluids. The marked heterogeneity evident in the sandy portion of a single 3 to 30-foot thick fluvial point bar deposit can exert significant differences in porous flow. Preferential permeability has been shown parallel to the long axis of fluvial channel sand units while barrier beach sands exhibit preferential permeability perpendicular to the long axis of the sand body. Such controls influence natural flow and transport of contaminants in groundwater. Hydrogeologic studies should: determine the depositional environment and facies present at the site; determine the propensity for heterogeneity within the entire vertical sequence investigated and within the different facies present; assess the potential for preferential permeability within sand bodies; and provide a predictive depositional model to assess potential connections between major high permeability units. Sand unit connections are commonly forced during cross section generation and subsequent aquifer analysis. Failure to incorporate the above objectives in hydrogeologic investigations ignores the basic precept that process controls the distribution of permeability and will result in poor prediction of natural and remedial transport of contaminants in groundwater

Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

Directory of Open Access Journals (Sweden)

S. ADHIKARI

2011-02-01

Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

Qualitative assessment of selected areas of the world for undiscovered sediment-hosted stratabound copper deposits: Chapter Y in Global mineral resource assessment

Science.gov (United States)

Zientek, Michael L.; Wintzer, Niki E.; Hayes, Timothy S.; Parks, Heather L.; Briggs, Deborah A.; Causey, J. Douglas; Hatch, Shyla A.; Jenkins, M. Christopher; Williams, David J.; Zientek, Michael L.; Hammarstrom, Jane M.; Johnson, Kathleen M.

2015-12-14

A qualitative mineral resource assessment of sediment-hosted stratabound copper mineralized areas for undiscovered copper deposits was performed for 10 selected areas of the world. The areas, in alphabetical order, are (1) Belt-Purcell Basin, United States and Canada; (2) Benguela and Cuanza Basins, Angola; (3) Chuxiong Basin, China; (4) Dongchuan Group rocks, China; (5) Egypt–Israel–Jordan Rift, Egypt, Israel, and Jordan; (6) Maritimes Basin, Canada; (7) Neuquén Basin, Argentina; (8) Northwest Botswana Rift, Botswana and Namibia; (9) Redstone Copperbelt, Canada; and (10) Salta Rift System, Argentina. This assessment (1) outlines the main characteristics of the areas, (2) classifies known deposits by deposit model subtypes, and (3) ranks the areas according to their potential to contain undiscovered copper deposits.

Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure

OpenAIRE

Michael Arthur Cuiffo; Jeffrey Snyder; Alicia M. Elliott; Nicholas Romero; Sandhiya Kannan; Gary P. Halada

2017-01-01

Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and pho...

Assessing Acid-Base Status: Physiologic Versus Physicochemical Approach.

Science.gov (United States)

Adrogué, Horacio J; Madias, Nicolaos E

2016-11-01

The physiologic approach has long been used in assessing acid-base status. This approach considers acids as hydrogen ion donors and bases as hydrogen ion acceptors and the acid-base status of the organism as reflecting the interaction of net hydrogen ion balance with body buffers. In the physiologic approach, the carbonic acid/bicarbonate buffer pair is used for assessing acid-base status and blood pH is determined by carbonic acid (ie, Paco 2 ) and serum bicarbonate levels. More recently, the physicochemical approach was introduced, which has gained popularity, particularly among intensivists and anesthesiologists. This approach posits that the acid-base status of body fluids is determined by changes in the dissociation of water that are driven by the interplay of 3 independent variables: the sum of strong (fully dissociated) cation concentrations minus the sum of strong anion concentrations (strong ion difference); the total concentration of weak acids; and Paco 2 . These 3 independent variables mechanistically determine both hydrogen ion concentration and bicarbonate concentration of body fluids, which are considered as dependent variables. Our experience indicates that the average practitioner is familiar with only one of these approaches and knows very little, if any, about the other approach. In the present Acid-Base and Electrolyte Teaching Case, we attempt to bridge this knowledge gap by contrasting the physiologic and physicochemical approaches to assessing acid-base status. We first outline the essential features, advantages, and limitations of each of the 2 approaches and then apply each approach to the same patient presentation. We conclude with our view about the optimal approach. Copyright © 2016 National Kidney Foundation, Inc. All rights reserved.

Stream chemistry in the eastern United States. 2. Current sources of acidity in acidic and low acid-neutralizing-capacity streams

International Nuclear Information System (INIS)

Herlihy, A.T.; Kaufmann, P.R.; Mitch, M.E.

1991-01-01

The authors examined anion composition in National Stream Survey (NSS) data in order to evaluate the most probable sources of current acidity in acidic and low acid neutralizing capacity (ANC) streams in the eastern United States. Acidic streams that had almost no organic influence (less than 10% of total anions) and sulfate and nitrate concentrations indicative of evaporative concentration of atmospheric deposition were classified as acidic due to acidic deposition. These acidic streams were located in small forested watersheds in the Mid-Atlantic Highlands (an estimated 1950 km of stream length) and in the Mid-Atlantic Coastal Plain (1250 km). Acidic streams affected primarily by acidic deposition but also influenced by naturally occurring organic anions accounted for another 1180 km of acidic stream length and were located in the New Jersey Pine Barrens, plateau tops in the Mid-Atlantic and Southeast Highlands, and the Florida Panhandle. The total length of streams acidic due to acid mine drainage in the NSS (4590 km) was about the same as the total length of acidic streams likely affected by acidic deposition (4380 km). Acidic streams whose acid anion composition was dominated by organics were located in Florida and the Mid-Atlantic Coastal Plain. In Florida, most of the acidic streams were organic dominated, whereas about half of the streams in the Mid-Atlantic Coastal Plain were organic dominated. Organic-dominated acidic streams were not observed in the Mid-Atlantic and Southeast Highlands

Risk assessment of metals in road-deposited sediment along an urban–rural gradient

International Nuclear Information System (INIS)

Zhao, Hongtao; Li, Xuyong

2013-01-01

We applied the traditional risk assessment methods originally designed for soils and river sediments to evaluation of risk associated with metals in road-deposited sediment (RDS) along an urban–rural gradient that included central urban (UCA), urban village (UVA), central suburban county (CSA), rural town (RTA), and rural village (RVA) areas in the Beijing metropolitan region. A new indicator RI RDS was developed which integrated the RDS characteristics of mobility, grain size and amount with the potential ecological risk index. The risk associated with metals in RDS in urban areas was generally higher than that in rural areas based on the assessment using traditional methods, but the risk was higher in urban and rural village areas than the areas with higher administration units based on the indicator RI RDS . These findings implied that RDS characteristics variation with the urban–rural gradient must be considered in metal risk assessment and RDS washoff pollution control. Highlights: ► Spatial pattern of metal risk level associated with road-deposited sediment (RDS) along urban–rural gradients varied. ► Risk level of metals changed significantly when grain size was considered. ► A new index integrating RDS characteristics and potential ecological risk was developed. ► Results from the new index were improved relative to those of traditional assessment methods. -- A new index integrating road-deposited sediment characteristics and potential ecological risk was developed to assess metal risk along the urban–rural gradient

Methods of mineral potential assessment of uranium deposits: A mineral systems approach

International Nuclear Information System (INIS)

Jaireth, S.

2014-01-01

Mineral potential represents the likelihood (probability) that an economic mineral deposit could have formed in an area. Mineral potential assessment and prospectivity analysis use a probabilistic concepts to mineral deposits, where the probability of an event (formation of a mineral deposit) is conditional on two factors : i) geological processes occurring in the area, and ii) the presence of geological features indicative of those process. For instance, one of the geological processes critical for the formation of sandstone-hosted uranium deposits in an area is transport of uranium in groundwaters. Geological features indicative of this process in an area comprise, i) presence of leachable source rocks of uranium; ii) presence of highly permeable sandstone; and iii) suitable hydrogeological gradient driving flow groundwaters. Mineral deposits can also be conceptualised as mineral systems with more emphasis on mineralising processes. This concept has some clear parallels with the petroleum systems approach which has proven to be a useful in oil and gas exploration. Mineral systems are defined as ‘all geological factors that control the generation and preservation of mineral deposits’. Seven important geological factors are outlined to define the characteristics of a hydrothermal mineral system. These factors include: i) source of the mineralising fluids and transporting legends; ii) source of metals and other ore components; iii) migration pathways which may include inflow as well as outflow zones; iv) thermal gradients; v) source of energy to mobilised fluids; vi) mechanical and structural focusing mechanism at the trap site; and vii) chemical and/or physical cause for precipitation of ore minerals at the trap site. This approach, commonly known as the ‘source’, ‘transport’ and ‘trap’ paradigm has been redefined to introduce five questions as a basis to understand spatial and temporal evolution of a mineral system at all scales (regional to

Proceedings for a Workshop on Deposit Modeling, Mineral Resource Assessment, and Their Role in Sustainable Development

Science.gov (United States)

Briskey, Joseph A.; Schulz, Klaus J.

2007-01-01

The world's use of nonfuel mineral resources continues to increase to support a growing population and increasing standards of living. The ability to meet this increasing demand is affected especially by concerns about possible environmental degradation associated with minerals production and by competing land uses. What information does the world need to support global minerals development in a sustainable way?Informed planning and decisions concerning sustainability and future mineral resource supply require a long–term perspective and an integrated approach to resource, land use, economic, and environmental management worldwide. Such perspective and approach require unbiased information on the global distribution of identified and especially undiscovered resources, the economic and political factors influencing their development, and the potential environmental consequences of their exploitation.The U.S. Geological Survey and the former Deposit Modeling Program of the International Union of Geological Sciences (IUGS) of the United Nations Educational, Scientific and Cultural Organization (UNESCO) sponsored a workshop on "Deposit Modeling, Mineral Resource Assessment, and Their Role in Sustainable Development" at the 31st International Geological Congress (IGC) in Rio de Janeiro, Brazil, on August 18–19, 2000. The purpose of the workshop was to review the state-of-the-art in mineral deposit modeling and resource assessment and to examine the role of global assessments of nonfuel mineral resources in sustainable development.The workshop addressed questions such as the following: Which of the available mineral deposit models and assessment methods are best suited for predicting the locations, deposit types, and amounts of undiscovered nonfuel mineral resources remaining in the world? What is the availability of global geologic, mineral deposit, and mineral exploration information? How can mineral resource assessments be used to address economic and

Effects of Acidic Deposition and Soil Acidification on Sugar Maple Trees in the Adirondack Mountains, New York

Science.gov (United States)

T. J. Sullivan; G. B. Lawrence; S. W. Bailey; T. C. McDonnell; C. M. Beier; K. C. Weathers; G. T. McPherson; D. A. Bishop

2013-01-01

We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been...

Assessment of Global Mercury Deposition through Litterfall.

Science.gov (United States)

Wang, Xun; Bao, Zhengduo; Lin, Che-Jen; Yuan, Wei; Feng, Xinbin

2016-08-16

There is a large uncertainty in the estimate of global dry deposition of atmospheric mercury (Hg). Hg deposition through litterfall represents an important input to terrestrial forest ecosystems via cumulative uptake of atmospheric Hg (most Hg(0)) to foliage. In this study, we estimate the quantity of global Hg deposition through litterfall using statistical modeling (Monte Carlo simulation) of published data sets of litterfall biomass production, tree density, and Hg concentration in litter samples. On the basis of the model results, the global annual Hg deposition through litterfall is estimated to be 1180 ± 710 Mg yr(-1), more than two times greater than the estimate by GEOS-Chem. Spatial distribution of Hg deposition through litterfall suggests that deposition flux decreases spatially from tropical to temperate and boreal regions. Approximately 70% of global Hg(0) dry deposition occurs in the tropical and subtropical regions. A major source of uncertainty in this study is the heterogeneous geospatial distribution of available data. More observational data in regions (Southeast Asia, Africa, and South America) where few data sets exist will greatly improve the accuracy of the current estimate. Given that the quantity of global Hg deposition via litterfall is typically 2-6 times higher than Hg(0) evasion from forest floor, global forest ecosystems represent a strong Hg(0) sink.

Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

Science.gov (United States)

He, Xia; Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J; de los Reyes, Francis L

2011-05-15

The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride. The calcium and fatty acid profile analysis showed that the laboratory-produced FOG deposit displayed similar characteristics to FOG deposits collected from sanitary sewer lines. Results of FTIR analysis showed that the FOG deposits are metallic salts of fatty acid as revealed by comparisons with FOG deposits collected from sewer lines and pure calcium soaps. Based on the data, we propose that the formation of FOG deposits occurs from the aggregation of excess calcium compressing the double layer of free fatty acid micelles and a saponification reaction between aggregated calcium and free fatty acids.

Evaluation of different approaches for modeling effects of acid rain on soils in China

International Nuclear Information System (INIS)

Larssen, T.; Schnoor, J.L.; Seip, H.M.; Dawei, Z.

2000-01-01

Acid deposition is an environmental problem of increasing concern in China. Acidic soils are common in the southern part of the country and soil acidification caused by acid deposition is expected to occur. Here we test and apply two different approaches for modeling effects of acid deposition and compare results with observed data from sites throughout southern China. The dynamic model MAGIC indicates that, during the last few decades, soil acidification rates have increased considerably due to acid deposition. This acidification will continue if sulfur deposition is not reduced, and if reduced more rapidly than base cation deposition. With the Steady State Mass Balance model (SSMB), and assuming that a molar ratio of Ca 2+ /Al 3+ <1 in soil water is harmful to vegetation, we estimate a slight probability for exceedance of the critical load for present deposition rates. Results from both modeling approaches show a strong dependence with deposition of base cations as well as sulfur. Hence, according to the models, changes in emission control of alkaline particulate matter prior to sulfur dioxide will be detrimental to the environment. Model calculations are, however, uncertain, particularly because available data on base cation deposition fluxes are scarce, and that model formulation of aluminum chemistry does not fully reproduce observations. An effort should be made to improve our present knowledge regarding deposition fluxes. Improvements to the model are suggested. Our work indicates that the critical loads presented in the regional acid deposition assessment model RAINS-Asia are too stringent. We find weaknesses in the SSMB approach, developed for northern European conditions, when applying it to Chinese conditions. We suggest an improved effort to revise the risk parameters for use in critical load estimates in China

Protein and lipid deposition rates in male broiler chickens : separate responses to amino acids and protein-free energy

NARCIS (Netherlands)

Eits, R.M.; Kwakkel, R.P.; Verstegen, M.W.A.; Stoutjesdijk, P.; Greef, de K.H.

2002-01-01

Two experiments of similar design were conducted with male broiler chickens over two body weight ranges, 200 to 800 g in Experiment 1 and 800 to 1,600 g in Experiment 2. The data were used to test the hypothesis that protein deposition rate increases (linearly) with increasing amino acid intake,

Danburite decomposition by hydrochloric acid

International Nuclear Information System (INIS)

Mamatov, E.D.; Ashurov, N.A.; Mirsaidov, U.

2011-01-01

Present article is devoted to decomposition of danburite of Ak-Arkhar Deposit of Tajikistan by hydrochloric acid. The interaction of boron containing ores of Ak-Arkhar Deposit of Tajikistan with mineral acids, including hydrochloric acid was studied. The optimal conditions of extraction of valuable components from danburite composition were determined. The chemical composition of danburite of Ak-Arkhar Deposit was determined as well. The kinetics of decomposition of calcined danburite by hydrochloric acid was studied. The apparent activation energy of the process of danburite decomposition by hydrochloric acid was calculated.

Leaching of cell wall components caused by acid deposition on fir needles and trees

Energy Technology Data Exchange (ETDEWEB)

Shigihara, Ado [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)], E-mail: r200670202@kanagawa-u.ac.jp; Matsumoto, Kiyoshi [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan); Sakurai, Naoki [Faculty of Integrated Arts and Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, 739-8521 (Japan); Igawa, Manabu [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)

2008-07-15

Virgin fir forests have been declining since the 1960s at Mt. Oyama, which is located at the eastern edge of the Tanzawa Mountains and adjacent to the Kanto plain in Japan. An acid fog frequently occurs in the mountains. We collected throughfall and stemflow under fir trees and rainfall every week during January-December 2004 at Mt. Oyama to clarify the influence of acid fog on the decline of fir (Abies firma) needles. In relation to throughfall and stemflow, D-mannose, D-galactose, and D-glucose are the major neutral sugar components; only D-glucose is a major component of rainfall. The correlation coefficient between the total neutral sugars and uronic acid (as D-galacturonic acid), which is a key component of the cross-linking between pectic polysaccharides, was high except for rainfall. The leached amount of calcium ion, neutral sugars, uronic acid, and boron is related to the nitrate ion concentration in throughfall. Results of a laboratory exposure experiment using artificial fog water simulating the average composition of fog water observed at Mt. Oyama (simulated acid fog: SAF) on the fir seedling needles also shows a large leaching of these components from the cell walls of fir needles. The leaching amount increased concomitantly with decreasing pH of the SAF solution. We also observed that a dimeric rhamnogalacturonan II-borate complex (dRG-II-B) that exists in the cell wall as pectic polysaccharide was converted to monomeric RG-II (mRG-II) by the leaching of calcium ion and boron. Results not only of field observations but also those of laboratory experiments indicate a large effect of acid depositions on fir needles.

Transcriptomic Analysis Identifies Candidate Genes Related to Intramuscular Fat Deposition and Fatty Acid Composition in the Breast Muscle of Squabs (Columba

Directory of Open Access Journals (Sweden)

Manhong Ye

2016-07-01

Full Text Available Despite the fact that squab is consumed throughout the world because of its high nutritional value and appreciated sensory attributes, aspects related to its characterization, and in particular genetic issues, have rarely been studied. In this study, meat traits in terms of pH, water-holding capacity, intramuscular fat content, and fatty acid profile of the breast muscle of squabs from two meat pigeon breeds were determined. Breed-specific differences were detected in fat-related traits of intramuscular fat content and fatty acid composition. RNA-Sequencing was applied to compare the transcriptomes of muscle and liver tissues between squabs of two breeds to identify candidate genes associated with the differences in the capacity of fat deposition. A total of 27 differentially expressed genes assigned to pathways of lipid metabolism were identified, of which, six genes belonged to the peroxisome proliferator-activated receptor signaling pathway along with four other genes. Our results confirmed in part previous reports in livestock and provided also a number of genes which had not been related to fat deposition so far. These genes can serve as a basis for further investigations to screen markers closely associated with intramuscular fat content and fatty acid composition in squabs. The data from this study were deposited in the National Center for Biotechnology Information (NCBI’s Sequence Read Archive under the accession numbers SRX1680021 and SRX1680022. This is the first transcriptome analysis of the muscle and liver tissue in Columba using next generation sequencing technology. Data provided here are of potential value to dissect functional genes influencing fat deposition in squabs.

A two-layer application of the MAGIC model to predict the effects of land use scenarios and reductions in deposition on acid sensitive soils in the UK

Directory of Open Access Journals (Sweden)

R. C. Helliwell

1998-01-01

Full Text Available A two-layer application of the catchment-based soil and surface water acidification model, MAGIC, was applied to 21 sites in the UK Acid Waters Monitoring Network (AWAMN, and the results were compared with those from a one-layer application of the model. The two-layer model represented typical soil properties more accurately by segregating the organic and mineral horizons into two separate soil compartments. Reductions in sulphur (S emissions associated with the Second S Protocol and different forestry (land use scenarios were modelled, and their effects on soil acidification evaluated. Soil acidification was assessed in terms of base saturation and critical loads for the molar ratio of base cations (CA2+ + MG 2+ + K+ to aluminium (Al in soil solution. The results of the two-layer application indicate that base saturation of the organic compartment was very responsive to changes in land use and deposition compared with the mineral soil. With the two- layer model, the organic soil compartment was particularly sensitive to acid deposition, which resulted in the critical load being predicted to be exceeded at eight sites in 1997 and two sites in 2010. These results indicate that further reductions in S deposition are necessary to raise the base cation (BC:Al ratio above the threshold which is harmful to tree roots. At forested sites BC:Al ratios were generally well below the threshold designated for soil critical loads in Europe and forecasts indicate that forest replanting can adversely affect the acid status of sensitive term objectives of protecting and sustaining soil and water quality. Policy formulation must seek to protect the most sensitive environmental receptor, in this case organic soils. It is clear, therefore, that simply securing protection of surface waters, via the critical loads approach, may not ensure adequate protection of low base status organic soils from the effects of acidification.

Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

Energy Technology Data Exchange (ETDEWEB)

McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D. [Oak Ridge National Lab., TN (United States)] [and others

1996-10-16

This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

Assessment of radon-daughter deposition in the respiratory tract

International Nuclear Information System (INIS)

Oberstedt, S.; Vanmarcke, H.

1996-01-01

Since some decades it is known, that most of the radiation dose to the lung is due to the inhalation of the short-lived decay products of 222 Rn. Their deposition in the respiratory tract strongly depends on the attachment rate to aerosol-particles present in the indoor air and their plate-out rate to the surfaces, instead of measuring the activity size distribution of the airborne decay products, knowledge on the respiratory tract retention has been incorporated in the design of a measurement system, called bronchial dosemeter, to assess the lung dose directly. The simulation of the deposition characteristics of the short-lived radon daughters in the nasal cavity and the bronchial tree is based on the comparison of the model of the respiratory tract with results from screen penetration theory. A bronchial dosemeter consisting of three sampling heads has been built and calibrated. Additionally, an outline of future activities will be given. (author)

Human health risk assessment of lead pollution in atmospheric deposition in Baoshan District, Shanghai.

Science.gov (United States)

Chen, Yuanyuan; Wang, Jun; Shi, Guitao; Sun, Xiaojing; Chen, Zhenlou; Xu, Shiyuan

2011-12-01

The lead (Pb) content in atmospheric deposition was determined at 42 sampling sites in Baoshan District of Shanghai, China. Based on exposure and dose-response assessments, the health risk caused by Pb exposure in atmospheric deposition was investigated. The results indicated that Pb was significantly accumulated in atmospheric deposition. The spatial distribution of Pb was mapped by geostatistical analysis, and the results showed that pollution hotspots were present at traffic and industrial zones. Ingestion was the main route of Pb exposure in both adults and children. For children the risk value was above 1, whereas it was below 1 for the adult group. Therefore, children belong to the high-risk group for Pb exposure from atmospheric deposition in the observed area of Shanghai, China.

Deposition of lignin droplets produced during dilute acid pretreatment of maize stems retards enzymatic hydrolysis of cellulose.

Science.gov (United States)

Selig, Michael J; Viamajala, Sridhar; Decker, Stephen R; Tucker, Melvin P; Himmel, Michael E; Vinzant, Todd B

2007-01-01

Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these "lignin" droplets and the possible implications they might have on the enzymatic saccharification of pretreated biomass. It was demonstrated that these droplets are produced from corn stover during pretreatment under neutral and acidic pH at and above 130 degrees C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150 degrees C) and captured onto pure cellulose was shown to have a negative effect (5-20%) on the enzymatic saccharification of this substrate. It was noted that droplet density (per unit area) was greater and droplet size more variable under conditions where the greatest impact on enzymatic cellulose conversion was observed. These results indicate that this phenomenon has the potential to adversely affect the efficiency of enzymatic conversion in a lignocellulosic biorefinery.

2.4. The kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit. The experimental data of dependence of hydrochloric-acid decomposition of calcined boron raw material for boron oxide extraction on temperature (20-80 deg C) and process duration (15-60 min) were considered. It was defined that at temperature increasing the boron oxide extraction from borosilicate raw material increases from 24.1 till 86.8%. The constants of decomposition rate of boron raw material were calculated.

The response of gene expression associated with lipid metabolism, fat deposition and fatty acid profile in the longissimus dorsi muscle of Gannan yaks to different energy levels of diets.

Directory of Open Access Journals (Sweden)

Chao Yang

Full Text Available The energy available from the diet, which affects fat deposition in vivo, is a major factor in the expression of genes regulating fat deposition in the longissimus dorsi muscle. Providing high-energy diets to yaks might increase intramuscular fat deposition and fatty acid concentrations under a traditional grazing system in cold seasons. A total of fifteen adult castrated male yaks with an initial body weight 274.3 ± 3.14 kg were analyzed for intramuscular adipose deposition and fatty acid composition. The animals were divided into three groups and fed low-energy (LE: 5.5 MJ/kg, medium-energy (ME: 6.2 MJ/kg and high-energy (HE: 6.9 MJ/kg diets, respectively. All animals were fed ad libitum twice daily at 08:00-09:00 am and 17:00-18:00 pm and with free access to water for 74 days, including a 14-d period to adapt to the diets and the environment. Intramuscular fat (IMF content, fatty acid profile and mRNA levels of genes involved in fatty acid synthesis were determined. The energy levels of the diets significantly (P<0.05 affected the content of IMF, total SFA, total MUFA and total PUFA. C16:0, C18:0 and C18:1n9c account for a large proportion of total fatty acids. Relative expression of acetyl-CoA carboxylase (ACACA, fatty acid synthase (FASN, stearoyl-CoA desaturase (SCD, sterol regulatory element-binding protein-1c (SREBP-1c, peroxisome proliferator-activated receptor γ (PPARγ and fatty acid-binding protein 4 (FABP4 was greater in HE than in LE yaks (P<0.05. Moreover, ME yaks had higher (P<0.05 mRNA expression levels of PPARγ, ACACA, FASN, SCD and FABP4 than did the LE yaks. The results demonstrate that the higher energy level of the diets increased IMF deposition and fatty acid content as well as increased intramuscular lipogenic gene expression during the experimental period.

Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, M.; Venkatesan, K.A.; Sudha, R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Srinivasan, T.G., E-mail: tgs@igcar.gov.com [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Vasudeva Rao, P.R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

2011-07-15

Research highlights: {yields} Platinum group metals are man-made noble metals. {yields} Electrochemical recovery of fission platinoids. {yields} Recovery from nitric acid medium. {yields} Recovery from ionic liquid medium. {yields} Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

Acid Rain

Science.gov (United States)

Bricker, Owen P.; Rice, Karen C.

1995-01-01

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

Different sources of omega-3 polyunsaturated fatty acids affects apparent digestibility, tissue deposition, and tissue oxidative stability in growing female rats

Directory of Open Access Journals (Sweden)

Benedito Vagner A

2011-10-01

Full Text Available Abstract Background Numerous health benefits associated with increased omega-3 polyunsaturated fatty acid (n-3 PUFA consumption has lead to an increasing variety of available n-3 PUFA sources. However, sources differ in the type, amount, and structural form of the n-3 PUFAs. Therefore, the objective of this study was to determine the effect of different sources of ω-3 PUFAs on digestibility, tissue deposition, eicosanoid metabolism, and oxidative stability. Methods Female Sprague-Dawley rats (age 28 d were randomly assigned (n = 10/group to be fed a high fat 12% (wt diet consisting of either corn oil (CO or n-3 PUFA rich flaxseed (FO, krill (KO, menhaden (MO, salmon (SO or tuna (TO oil for 8 weeks. Rats were individually housed in metabolic cages to determine fatty acid digestibility. Diet and tissue fatty acid composition was analyzed by gas chromatography and lipid classes using thin layer chromatography. Eicosanoid metabolism was determined by measuring urinary metabolites of 2-series prostaglandins (PGs and thromoboxanes (TXBs using enzyme immunoassays. Oxidative stability was assessed by measuring thiobarbituric acid reactive substances (TBARS and total antioxidant capacity (TAC using colorimetric assays. Gene expression of antioxidant defense enzymes was determined by real time quantitative polymerase chain reaction (RT-qPCR. Results Rats fed KO had significantly lower DHA digestibility and brain DHA incorporation than SO and TO-fed rats. Of the n-3 PUFA sources, rats fed SO and TO had the highest n-3 PUFAs digestibility and in turn, tissue accretion. Higher tissue n-3 LC-PUFAs had no significant effect on 2-series PG and TXB metabolites. Despite higher tissue n-3 LC-PUFA deposition, there was no increase in oxidation susceptibility indicated by no significant increase in TBARS or decrease in TAC and gene expression of antioxidant defense enzymes, in SO or TO-fed rats. Conclusions On the basis that the optimal n-3 PUFA sources should

Effect of PW12–GPK on the acid characteristics of Ni-, Pd- and Pt- catalysts deposited onto pillared Al montmorillonite

Directory of Open Access Journals (Sweden)

D. Zhumadullaev

2012-03-01

Full Text Available Acid characteristics of Ni-, Pd-, Pt- catalyzers , deposited to Al pillared CaH montmorillonite modified by heteropolyacid H3PW12O40·xH2O (PW12 by ammonia thermoadsorbtion method has been studied.

The smog-fog-smog cycle and acid deposition

Science.gov (United States)

Pandis, Spyros N.; Seinfeld, John H.; Pilinis, Christodoulos

1990-10-01

A model including descriptions of aerosol and droplet microphysics, gas and aqueous-phase chemistry, and deposition is used to study the transformation of aerosol to fog droplets and back to aerosol in an urban environment. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium and well as in the total aerosol mass concentration. The sulfate produced during fog episodes favors the aerosol particles that have access to most of the fog liquid water which are usually the large particles. Aerosol scavenging efficiencies of around 80 percent are calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition and can introduce errors in the reported values of the ionic species deposition velocities. Differences in the major ionic species deposition velocities can be explained by their distribution over the droplet size spectrum and can be correlated with the species average diameter. Two different expressions are derived for use in fog models for the calculation of the liquid water deposition velocity during fog growth and dissipation stages.

Effects of simulated deposition of acid mist and iron ore particulate matter on photosynthesis and the generation of oxidative stress in Schinus terebinthifolius Radii and Sophora tomentosa L.

Science.gov (United States)

Kuki, Kacilda Naomi; Oliva, Marco Antônio; Pereira, Eduardo Gusmão; Costa, Alan Carlos; Cambraia, José

2008-09-15

Particulate matter is a natural occurrence in the environment, but some industries, such as the iron ore sector, can raise the total amount of particles in the atmosphere. This industry is primarily a source of iron and sulfur dioxide particulates. The effects of the pollutants from the iron ore industries on representatives of restinga vegetation in a Brazilian coastal ecosystem were investigated using physiological and biochemical measures. Two species, Schinus terebinthifolius and Sophora tomentosa, were exposed to simulated deposition of acid mist and iron ore particulate matter in acrylic chambers in a greenhouse. Parameters such as gas exchange, fluorescence emission, chlorophyll content, total iron content, antioxidant enzyme activity and malondialdehyde content were assessed in order to evaluate the responses of the two species. Neither treatment was capable of inducing oxidative stress in S. terebinthifolius. Nevertheless, the deposition of iron ore particulates on this species increased chlorophyll content, the maximum quantum efficiency of photosystem II and the electron transport rate, while iron content was unaltered. On the other hand, S. tomentosa showed a greater sensitivity to the treatments. Plants of S. tomentosa that were exposed to acid mist had a decrease in photosynthesis, while the deposition of iron particulate matter led to an increase in iron content and membrane permeability of the leaves. The activities of antioxidant enzymes, such as catalases and superoxide dismutase, were enhanced by both treatments. The results suggested that the two restinga species use different strategies to overcome the stressful conditions created by the deposition of particulate matter, either solid or wet. It seems that while S. terebinthifolius avoided stress, S. tomentosa used antioxidant enzyme systems to partially neutralize oxidative stress. The findings also point to the potential use of S. tomentosa as a biomarker species under field conditions.

Effects of simulated deposition of acid mist and iron ore particulate matter on photosynthesis and the generation of oxidative stress in Schinus terebinthifolius Radii and Sophora tomentosa L

Energy Technology Data Exchange (ETDEWEB)

Kuki, Kacilda Naomi [Departamento de Biologia Vegetal, Universidade Federal de Vicosa (Brazil)], E-mail: naomikuki@hotmail.com; Oliva, Marco Antonio; Pereira, Eduardo Gusmao; Costa, Alan Carlos [Departamento de Biologia Vegetal, Universidade Federal de Vicosa (Brazil); Cambraia, Jose [Departamento de Biologia Geral, Universidade Federal de Vicosa (Brazil)

2008-09-15

Particulate matter is a natural occurrence in the environment, but some industries, such as the iron ore sector, can raise the total amount of particles in the atmosphere. This industry is primarily a source of iron and sulfur dioxide particulates. The effects of the pollutants from the iron ore industries on representatives of restinga vegetation in a Brazilian coastal ecosystem were investigated using physiological and biochemical measures. Two species, Schinus terebinthifolius and Sophora tomentosa, were exposed to simulated deposition of acid mist and iron ore particulate matter in acrylic chambers in a greenhouse. Parameters such as gas exchange, fluorescence emission, chlorophyll content, total iron content, antioxidant enzyme activity and malondialdehyde content were assessed in order to evaluate the responses of the two species. Neither treatment was capable of inducing oxidative stress in S. terebinthifolius. Nevertheless, the deposition of iron ore particulates on this species increased chlorophyll content, the maximum quantum efficiency of photosystem II and the electron transport rate, while iron content was unaltered. On the other hand, S. tomentosa showed a greater sensitivity to the treatments. Plants of S. tomentosa that were exposed to acid mist had a decrease in photosynthesis, while the deposition of iron particulate matter led to an increase in iron content and membrane permeability of the leaves. The activities of antioxidant enzymes, such as catalases and superoxide dismutase, were enhanced by both treatments. The results suggested that the two restinga species use different strategies to overcome the stressful conditions created by the deposition of particulate matter, either solid or wet. It seems that while S. terebinthifolius avoided stress, S. tomentosa used antioxidant enzyme systems to partially neutralize oxidative stress. The findings also point to the potential use of S. tomentosa as a biomarker species under field conditions.

Effects of simulated deposition of acid mist and iron ore particulate matter on photosynthesis and the generation of oxidative stress in Schinus terebinthifolius Radii and Sophora tomentosa L

International Nuclear Information System (INIS)

Kuki, Kacilda Naomi; Oliva, Marco Antonio; Pereira, Eduardo Gusmao; Costa, Alan Carlos; Cambraia, Jose

2008-01-01

Particulate matter is a natural occurrence in the environment, but some industries, such as the iron ore sector, can raise the total amount of particles in the atmosphere. This industry is primarily a source of iron and sulfur dioxide particulates. The effects of the pollutants from the iron ore industries on representatives of restinga vegetation in a Brazilian coastal ecosystem were investigated using physiological and biochemical measures. Two species, Schinus terebinthifolius and Sophora tomentosa, were exposed to simulated deposition of acid mist and iron ore particulate matter in acrylic chambers in a greenhouse. Parameters such as gas exchange, fluorescence emission, chlorophyll content, total iron content, antioxidant enzyme activity and malondialdehyde content were assessed in order to evaluate the responses of the two species. Neither treatment was capable of inducing oxidative stress in S. terebinthifolius. Nevertheless, the deposition of iron ore particulates on this species increased chlorophyll content, the maximum quantum efficiency of photosystem II and the electron transport rate, while iron content was unaltered. On the other hand, S. tomentosa showed a greater sensitivity to the treatments. Plants of S. tomentosa that were exposed to acid mist had a decrease in photosynthesis, while the deposition of iron particulate matter led to an increase in iron content and membrane permeability of the leaves. The activities of antioxidant enzymes, such as catalases and superoxide dismutase, were enhanced by both treatments. The results suggested that the two restinga species use different strategies to overcome the stressful conditions created by the deposition of particulate matter, either solid or wet. It seems that while S. terebinthifolius avoided stress, S. tomentosa used antioxidant enzyme systems to partially neutralize oxidative stress. The findings also point to the potential use of S. tomentosa as a biomarker species under field conditions

The effect of acid precipitation on tree growth in eastern North America

Science.gov (United States)

Charles V. Cogbill

1976-01-01

Detailed study of the history of forest tree growth by tree-ring analysis is used to assess the effect of acid precipitation. The pattern and historical trends of acid precipitation deposition are compared with growth trends from mature forest stands in New Hampshire and Tennessee. No clear indication of a regional, synchronized decrease in tree growth was found. The...

Whole-lake algal responses to a century of acidic industrial deposition on the Canadian Shield

International Nuclear Information System (INIS)

Vinebrooke, R.D.; Dixit, S.S.; Graham, M.D.; Gunn, J.M.; Chen, Y.-W.; Belzile, N.

2002-01-01

A century of cultural acidification is hypothesized to have altered algal community structure in boreal lakes. To date, this hypothesis has remained untested because of both the lack of data predating the onset of industrial pollution and incomplete estimates of whole-lake algal community structure. High-pressure liquid chromatography (HPLC) of sedimentary pigments was used to quantify whole-lake algal responses to acid deposition in six boreal lakes located in Killarney Park, Ontario, Canada. Concomitant significant increases in chlorophyll and carotenoid concentrations, diatom-inferred lake acidity, and metal levels since 1900 suggested that algal abundances in four acidified lakes and one small, circumneutral lake were enhanced by aerial pollution. An alternate explanation is that increased acidity and underwater light availability in the acidified lakes shifted algal abundance towards phytobenthos and deepwater phytoplankton, whose pigment signatures were better preserved in the sediments. Taxonomically diagnostic pigment stratigraphies were consistent with shifts in algal community structure towards filamentous green phytobenthos and deepwater phytoflagellates in the acidified lakes. Our findings suggest that decades of aerial pollution have altered the base of foodwebs in boreal lakes, potentially rendering them less resilient to other environmental stressors. (author)

Sequential simulation approach to modeling of multi-seam coal deposits with an application to the assessment of a Louisiana lignite

Science.gov (United States)

Olea, Ricardo A.; Luppens, James A.

2012-01-01

There are multiple ways to characterize uncertainty in the assessment of coal resources, but not all of them are equally satisfactory. Increasingly, the tendency is toward borrowing from the statistical tools developed in the last 50 years for the quantitative assessment of other mineral commodities. Here, we briefly review the most recent of such methods and formulate a procedure for the systematic assessment of multi-seam coal deposits taking into account several geological factors, such as fluctuations in thickness, erosion, oxidation, and bed boundaries. A lignite deposit explored in three stages is used for validating models based on comparing a first set of drill holes against data from infill and development drilling. Results were fully consistent with reality, providing a variety of maps, histograms, and scatterplots characterizing the deposit and associated uncertainty in the assessments. The geostatistical approach was particularly informative in providing a probability distribution modeling deposit wide uncertainty about total resources and a cumulative distribution of coal tonnage as a function of local uncertainty.

Effect of glycerin and formic acid in the efficiency of deposit on Zn-Ni, obtained by electrodeposition; Efeito da glicerina e do acido formico na eficiencia de deposito da liga Zn-Ni, obtido atraves de eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Pedroza, G.A.G.; Souza, C.A.C.; Lima, L.R.P.A.; Ferreira, D.M. [Universidade Federal da Bahia - Escola Politecnica, BA (Brazil)

2010-07-01

Additives are added to the electrodeposition of metal coatings to improve the characteristics of the deposit. However, the objective was to investigate the effect of adding glycerin and formic acid in the deposition efficiency and deposit structure of zinc-nickel alloy obtained by electrodeposition. The depositions were made at a galvanostatic current density of 10 mA/cm{sup 2} to obtain a deposit of about 5 mm in thickness. The deposition efficiency was determined through measures of mass, chemical composition of the deposit in the presence and absence of additives was examined by X-ray Spectrometer Fluorescence (XRF) and surface characterization of coatings was performed by Scanning Electron Microscopy (SEM). The high levels of glycerin (0,07 M) and formic acid (0,26 M) in bath deposition increased the deposition efficiency of around 10% to 12% by mass, respectively. (author)

Photocatalytic activity of tin-doped TiO{sub 2} film deposited via aerosol assisted chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Chua, Chin Sheng, E-mail: cschua@simtech.a-star.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Tan, Ooi Kiang; Tse, Man Siu [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Ding, Xingzhao [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore)

2013-10-01

Tin-doped TiO{sub 2} films are deposited via aerosol assisted chemical vapor deposition using a precursor mixture composing of titanium tetraisopropoxide and tetrabutyl tin. The amount of tin doping in the deposited films is controlled by the volume % concentration ratio of tetrabutyl tin over titanium tetraisopropoxide in the mixed precursor solution. X-ray diffraction analysis results reveal that the as-deposited films are composed of pure anatase TiO{sub 2} phase. Red-shift in the absorbance spectra is observed attributed to the introduction of Sn{sup 4+} band states below the conduction band of TiO{sub 2}. The effect of tin doping on the photocatalytic property of TiO{sub 2} films is studied through the degradation of stearic acid under UV light illumination. It is found that there is a 10% enhancement on the degradation rate of stearic acid for the film with 3.8% tin doping in comparison with pure TiO{sub 2} film. This improvement of photocatalytic performance with tin incorporation could be ascribed to the reduction of electron-hole recombination rate through charge separation and an increased amount of OH radicals which are crucial for the degradation of stearic acid. Further increase in tin doping results in the formation of recombination site and large anatase grains, which leads to a decrease in the degradation rate. - Highlights: ► Deposition of tin-doped TiO{sub 2} film via aerosol assisted chemical vapor deposition ► Deposited anatase films show red-shifted in UV–vis spectrum with tin-dopants. ► Photoactivity improves at low tin concentration but reduces at higher concentration. ► Improvement in photoactivity due to bandgap narrowing from Sn{sup 4+} band states ► Maximum photoactivity achieved occurs for films with 3.8% tin doping.

Flow cytometric assessment of viability of lactic acid bacteria

NARCIS (Netherlands)

Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F.M.; Abee, T.

2001-01-01

The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA

Valproic acid reduces insulin-resistance, fat deposition and FOXO1-mediated gluconeogenesis in type-2 diabetic rat.

Science.gov (United States)

Khan, Sabbir; Kumar, Sandeep; Jena, Gopabandhu

2016-06-01

Recent evidences highlighted the role of histone deacetylases (HDACs) in insulin-resistance, gluconeogenesis and islet function. HDACs can modulate the expression of various genes, which directly or indirectly affect glucose metabolism. This study was aimed to evaluate the role of valproic acid (VPA) on fat deposition, insulin-resistance and gluconeogenesis in type-2 diabetic rat. Diabetes was developed in Sprague-Dawley rats by the combination of high-fat diet and low dose streptozotocin. VPA at the doses of 150 and 300 mg/kg/day and metformin (positive control) 150 mg/kg twice daily for 10 weeks were administered by oral gavage. Insulin-resistance, dyslipidemia and glycemia were evaluated by biochemical estimations, while fat accumulation and structural alteration were assessed by histopathology. Protein expression and insulin signaling were evaluated by western blot and immunohistochemistry. VPA treatment significantly reduced the plasma glucose, HbA1c, insulin-resistance, fat deposition in brown adipose tissue, white adipose tissue and liver, which are comparable to metformin treatment. Further, VPA inhibited the gluconeogenesis and glucagon expression as well as restored the histopathological alterations in pancreas and liver. Our findings provide new insights on the anti-diabetic role of VPA in type-2 diabetes mellitus by the modulation of insulin signaling and forkhead box protein O1 (FOXO1)-mediated gluconeogenesis. Since VPA is a well established clinical drug, the detailed molecular mechanisms of the present findings can be further investigated for possible clinical use. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

New insight into silica deposition in horsetail (Equisetum arvense

Directory of Open Access Journals (Sweden)

Exley Christopher

2011-07-01

Full Text Available Abstract Background The horsetails (Equisetum sp are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. Results Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. Conclusions The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.

Assessment of sand quality on concrete performance : examination of acidic and sulfate/sulfide-bearing sands.

Science.gov (United States)

2014-12-01

The purpose of this research is to examine how the presence of sulfide- and sulfate-containing : minerals in acidic aggregates may affect the properties of mortar and concrete. Analyses were : performed to compare two sands from a deposit in the Geor...

Treatment of acid drainage in uranium deposit by means of a natural wetland

International Nuclear Information System (INIS)

Grudeva, V.I.; Stoyanova, A.D.; Grudev, S.N.

2004-01-01

Acid drainage waters generated in the uranium deposit G-1, Western Bulgaria, were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 2.4-3.9 and contained uranium and radium radionuclides, heavy metals (copper, zinc , cadmium, iron, manganese) arsenic and sulfates in concentrations usually much higher than the relevant permissible levels for waters intended for use in agriculture and/or industry. The wetland was characterized by abundant and emergent vegetation and a diverse microflora. Typha latifolia, Typha augustifolia and Potamogeton australis were the main plant species in the wetland but representatives of the genera Scirpus, Juncus, Elepchoris, Potamogeton, Carex and Poa as well as different algae were also present. The water flows through the wetland varied in the range at about 0.2-1,2 l/s reflecting water residence times in the wetland of about 10-50 hours. An efficient water cleanup took place in the wetland even during the cold winter months at ambient temperatures close to 0 o C. The removal of pollutants was due to different processes but the microbial dissimilatory sulphate reduction and the sorption of pollutants on organic matter (living and dead plant and microbial biomass) and clays present in the wetland played the main role. (author)

Evaluation of physical and chemical properties and their interactions in fat, oil, and grease (FOG) deposits.

Science.gov (United States)

Gross, Martin A; Jensen, Jeanette L; Gracz, Hanna S; Dancer, Jens; Keener, Kevin M

2017-10-15

Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photoelectrocatalytic degradation of oxalic acid by spray deposited nanocrystalline zinc oxide thin films

International Nuclear Information System (INIS)

Shinde, S.S.; Shinde, P.S.; Sapkal, R.T.; Oh, Y.W.; Haranath, D.; Bhosale, C.H.; Rajpure, K.Y.

2012-01-01

Highlights: ► Influence of substrate temperature onto the physico-chemical properties. ► Photochemical, structural, luminescent, optoelectrical and thermal properties. ► The kinetics of oxalic acid degradation with reaction mechanism. ► Extent of mineralization by COD and TOC. - Abstract: The high quality nano-crystalline zinc oxide thin films are deposited onto corning glasses by spray pyrolysis technique. The influence of reaction temperature onto their photoelectrochemical, structural, morphological, optoelectronic, luminescence and thermal properties has been investigated. The structural characteristics studied by X-ray diffractometry has complemented by resistivity measurements and UV–Vis spectroscopy. The photoelectrochemical activity shows enhancement in short circuit current (I sc = 0.357 mA) and open circuit voltage (V oc = 0.48 V). Direct band gap calculated by considering R and T values of ZnO thin films increases from 3.14–3.21 eV exhibiting a slight blue shift in band edge. Three characteristic luminescence peaks having near band-edge, blue and green emission are observed in the photoluminescence spectra. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in films. Photocatalytic degradation of oxalic acid followed with reaction mechanism by using zinc oxide photoelectrode under solar illumination has been investigated.

1987 wet deposition temporal and spatial patterns in North America

Energy Technology Data Exchange (ETDEWEB)

Simpson, J.C.; Olsen, A.R.

1990-03-01

The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

Changes in stream chemistry and biology in response to reduced levels of acid deposition during 1987-2003 in the Neversink River Basin, Catskill Mountains

Science.gov (United States)

Burns, Douglas A.; Riva-Murray, K.; Bode, R.W.; Passy, S.

2008-01-01

Atmospheric acid deposition has decreased in the northeastern United States since the 1970s, resulting in modest increases in pH, acid-neutralizing capacity (ANC), and decreases in inorganic monomeric aluminum (AlIM) concentrations since stream chemistry monitoring began in the 1980s in the acid-sensitive upper Neversink River basin in the Catskill Mountains of New York. Stream pH has increased by 0.01 units/year during 1987-2003 at three sites in the Neversink basin as determined by Seasonal Kendall trend analysis. In light of this observed decrease in stream acidity, we sampled 12 stream sites within the Neversink River watershed for water chemistry, macroinvertebrates, fish, and periphytic diatoms in 2003 to compare with a similar data set collected in 1987. Metrics and indices that reflect sensitivity to stream acidity were developed with these biological data to determine whether changes in stream biota over the intervening 16 years parallel those of stream chemistry. Statistical comparisons of data on stream chemistry and an acid biological assessment profile (Acid BAP) derived from invertebrate data showed no significant differences between the two years. For pH and ANC, however, values in 2003 were generally lower than those in 1987; this difference likely resulted from higher streamflow in summer 2003. Despite these likely flow-induced changes in summer 2003, an ordination and cluster analysis of macroinvertebrate taxa based on the Acid BAP indicated that the most acidic sites in the upstream half of the East Branch Neversink River form a statistically significant separate cluster consistent with less acidic stream conditions. This analysis is consistent with limited recovery of invertebrate species in the most acidic reaches of the river, but will require additional improvement in stream chemistry before a stronger conclusion can be drawn. Data on the fish and periphytic diatom communities in 2003 indicate that slimy sculpin had not extended their habitat

Modelling atmospheric deposition flux of Cadmium and Lead in urban areas

International Nuclear Information System (INIS)

Cherin, Nicolas

2017-01-01

According to WHO, air pollution is responsible for more than 3.7 million premature deaths each year (OMS, 2014). Moreover, among these deaths, more than 70 within urban areas. Consequently, the health and environmental impacts of pollutants within these urban areas are of great concern in air quality studies. The deposition fluxes of air pollutants, which can be significant near sources of pollution, have rarely been modeled within urban areas. Historically, atmospheric deposition studies have focused mostly on remote areas to assess the potential impacts on ecosystems of acid deposition and nitrogen loading. Therefore, current atmospheric deposition models may not be suitable to simulate deposition fluxes in urban areas, which include complex surface geometries and diverse land use types. Atmospheric dry deposition is typically modeled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parameterize momentum and heat transfer. We extend this approach here to mass transfer, and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing-length parameterization of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially distributed dry deposition fluxes. This approach provides spatially distributed dry deposition fluxes depending on surfaces (streets, walls, roofs) and flow regimes (recirculation and ventilation) within the urban area. (author) [fr

Uranium deposits associated to tertiary acid volcanism of the Pena Blanca Sierra (Chihuahua, Mexico)

International Nuclear Information System (INIS)

Aniel, B.

1986-12-01

The uraniferous deposits located in the Sierra de Pena Blanca (Chihuahua, Mexico) are the consequence of successive events that modified acid volcanic rocks. The devitrification of the Nopal Formation, vitroclastic tuffs, is esential in the cooling history because it releases uranium that becomes available. The uranium present in fluids as uranylcarbonate complexes, precipitate along the lamellea of hematite (exsolutions of the ilmenites). The presence of sulfur causes the destabilization of the ilmenites with uranium oxide (pitchblende - titanium oxide - pyrite), the pseudomorph of magnetites (pitchblende - pyrite) and the transformation of hematite into pyrite. The silice coming from the kaolinization of feldspars recristallizes as microcristalline quartz so that the rock appears compact. Fractures cause the uplifting of the lower unit of Nopal formation. It has been altered to montmorillonite. A carbonatation of this tuff has been observed and these two types of alteration occur after kaolinization. The Escuadra formation overlies the Nopal formation. The deposition takes place on an eroded basement where a soil developed. The two formations will together undergo transformations due to the saturation level and the primary ore will be only oxidized or oxidized, transported and reconcentrated. Late and localized thermal activities have been observed and may be the result of tectonic movements occurring after the supergene modification [fr

Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

Science.gov (United States)

He, Xia; de los Reyes, Francis L; Leming, Michael L; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

2013-09-01

FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs). We report the first formation of FOG deposits on a concrete surface under laboratory conditions that mimic the formation of deposits in sewer systems. Results showed that calcium, the dominant metal in FOG deposits, can be released from concrete surfaces under low pH conditions and contribute to the formation process. Small amounts of additional oil to grease interceptor effluent substantially facilitated the air/water or pipe surface/water interfacial reaction between free fatty acids and calcium to produce surface FOG deposits. Tests of different fatty acids revealed that more viscous FOG deposit solids were formed on concrete surfaces, and concrete corrosion was accelerated, in the presence of unsaturated FFAs versus saturated FFAs. Based on all the data, a comprehensive model was proposed for the mechanisms of FOG deposit formation in sewer systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physicochemical aspects of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids

International Nuclear Information System (INIS)

Kayumov, A.M.

2018-01-01

The purpose of work is to study the processes of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids in temperature interval 20-98 deg C with the using of methods of selective extraction of valuable materials; elaboration of rational conditions of decomposition of raw material. Physicochemical properties of initial aluminium comprising ores, intermediate and final products of processing of argillites and green clays have been studied. Kinetic parameters of processes at acidic decomposition of argillites and green clays have been studied as well. The kinetic parameters of processes of decomposition of green clays and argillites by nitric and hydrochloric acids have been calculated. The flowsheet of complex processing of green clays and argillites of Chashma-Sang Deposit has been elaborated.

The urban perspectives of acid rain

International Nuclear Information System (INIS)

Tonn, B.E.

1993-01-01

This report documents discussions held during a workshop an Urban Perspective of Acid Rain. The workshop was sponsored by the Office of the Director, National Acid Precipitation Assessment Program (NAPAP). NAPAP anticipates giving increased emphasis to the benefits in urban areas of emissions reductions. The goal of this informal, exploratory workshop was to serve as a first step towards identifying pollutant monitoring, and research and assessment needs to help answer, from an urban perspective, the two key questions posed to NAPAP by Congress: (1) what are the costs, benefits, and effectiveness of the acid rain control program, and (2) what reductions in deposition, rates are needed in order to prevent adverse effects? The workshop addressed research activities needed to respond to these questions. The discussions focused. sequentially, on data needs, data and model availability, and data and modeling gaps. The discussions concentrated on four areas of effects: human health, materials, urban forests, and visibility

Rapid Deposition of Oxidized Biogenic Compounds to a Temperate Forest

Science.gov (United States)

Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

2015-01-01

We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (approx. 1 nmol m(exp.-2)·s(exp.-1)). GEOS-Chem, awidely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

[Pollution evaluation and health risk assessment of heavy metals from atmospheric deposition in Lanzhou].

Science.gov (United States)

Li, Ping; Xue, Su-Yin; Wang, Sheng-Li; Nan, Zhong-Ren

2014-03-01

In order to evaluate the contamination and health risk of heavy metals from atmospheric deposition in Lanzhou, samples of atmospheric deposition were collected from 11 sampling sites respectively and their concentrations of heavy metals were determined. The results showed that the average contents of Cu, Pb, Cd, Cr, Ni, Zn and Mn were 82.22, 130.31, 4.34, 88.73, 40.64, 369.23 and 501.49 mg x kg(-1), respectively. There was great difference among different functional areas for all elements except Mn. According to the results, the enrichment factor score of Mn was close to 1, while the enrichment of Zn, Ni, Cu and Cr was more serious, and Pb and Cd were extremely enriched. The assessment results of geoaccumulation index of potential ecological risk indicated that the pollution of Cd in the atmospheric deposition of Lanzhou should be classified as extreme degree, and that of Cu, Ni, Zn, Pb as between slight and extreme degrees, and Cr as practically uncontaminated. Contaminations of atmospheric dust by heavy metals in October to the next March were more serious than those from April to August. Health risk assessment indicated that the heavy metals in atmospheric deposition were mainly ingested by human bodies through hand-mouth ingestion. The non-cancer risk was higher for children than for adults. The order of non-cancer hazard indexes of heavy metals was Pb > Cr > Cd > Cu > Ni > Zn. The non-cancer hazard indexes and carcinogen risks of heavy metals were both lower than their threshold values, suggesting that they will not harm the health.

A conceptual framework: Redefining forest soil's critical acid loads under a changing climate

International Nuclear Information System (INIS)

McNulty, Steven G.; Boggs, Johnny L.

2010-01-01

. While the ecosystem was not in exceedance of the CAL, long-term nitrogen deposition pre-disposed the forest to other ecological stress. In combination, insects, drought, and nitrogen ultimately combined to cause the observed forest mortality. If any one of these factors were not present, the trees would likely not have died. This paper presents a conceptual framework of the ecosystem consequences of these interactions as well as limited plot level data to support this concept. Future assessments of the use of CAL studies need to account for multiple stress impacts to better understand ecosystem response. - Forests appear much less able to tolerate elevated acid loading when subjected to multiple stresses, thus future assessment of CALs and exceedances need to address the dynamic nature of multiple environmental stress if improvements in identifying areas of impaired forest health are to be achieved.

Air pollution: Tropospheric ozone, and wet deposition of sulfate and inorganic nitrogen

Science.gov (United States)

John W. Coulston

2009-01-01

The influence of air pollutants on ecosystems in the United States is an important environmental issue. The term “air pollution” encompasses a wide range of topics, but acid deposition and ozone are primary concerns in the context of forest health. Acid deposition partially results from emissions of sulfur dioxide, nitrogen oxides, and ammonia that are deposited in wet...

Advanced zirconia-coated carbonyl-iron particles for acidic magnetorheological finishing of chemical-vapor-deposited ZnS and other IR materials

Science.gov (United States)

Salzman, S.; Giannechini, L. J.; Romanofsky, H. J.; Golini, N.; Taylor, B.; Jacobs, S. D.; Lambropoulos, J. C.

2015-10-01

We present a modified version of zirconia-coated carbonyl-iron (CI) particles that were invented at the University of Rochester in 2008. The amount of zirconia on the coating is increased to further protect the iron particles from corrosion when introduced to an acidic environment. Five low-pH, magnetorheological (MR) fluids were made with five acids: acetic, hydrochloric, nitric, phosphoric, and hydrofluoric. All fluids were based on the modified zirconia-coated CI particles. Off-line viscosity and pH stability were measured for all acidic MR fluids to determine the ideal fluid composition for acidic MR finishing of chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and other infrared (IR) optical materials, such as hot-isostatic-pressed (HIP) ZnS, CVD zinc selenide (ZnSe), and magnesium fluoride (MgF2). Results show significant reduction in surface artifacts (millimeter-size, pebble-like structures on the finished surface) for several standard-grade CVD ZnS substrates and good surface roughness for the non-CVD MgF2 substrate when MR finished with our advanced acidic MR fluid.

Chiral Asymmetric Structures in Aspartic Acid and Valine Crystals Assessed by Atomic Force Microscopy.

Science.gov (United States)

Teschke, Omar; Soares, David Mendez

2016-03-29

Structures of crystallized deposits formed by the molecular self-assembly of aspartic acid and valine on silicon substrates were imaged by atomic force microscopy. Images of d- and l-aspartic acid crystal surfaces showing extended molecularly flat sheets or regions separated by single molecule thick steps are presented. Distinct orientation surfaces were imaged, which, combined with the single molecule step size, defines the geometry of the crystal. However, single molecule step growth also reveals the crystal chirality, i.e., growth orientations. The imaged ordered lattice of aspartic acid (asp) and valine (val) mostly revealed periodicities corresponding to bulk terminations, but a previously unreported molecular hexagonal lattice configuration was observed for both l-asp and l-val but not for d-asp or d-val. Atomic force microscopy can then be used to identify the different chiral forms of aspartic acid and valine crystals.

A methodological toolkit for field assessments of artisanally mined alluvial diamond deposits

Science.gov (United States)

Chirico, Peter G.; Malpeli, Katherine C.

2014-01-01

This toolkit provides a standardized checklist of critical issues relevant to artisanal mining-related field research. An integrated sociophysical geographic approach to collecting data at artisanal mine sites is outlined. The implementation and results of a multistakeholder approach to data collection, carried out in the assessment of Guinea’s artisanally mined diamond deposits, also are summarized. This toolkit, based on recent and successful field campaigns in West Africa, has been developed as a reference document to assist other government agencies or organizations in collecting the data necessary for artisanal diamond mining or similar natural resource assessments.

Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

International Nuclear Information System (INIS)

Hanson, Mark L.; Solomon, Keith R.

2004-01-01

Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC 10 ). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs. - Current environmental concentrations of haloacetic acids do not pose a risk to aquatic macrophytes, but could impact plankton

Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

Science.gov (United States)

Sağlam, Emine Selva; Akçay, Miğraç

2016-04-01

Being one of the largest copper-producing resources in Turkey, the Murgul deposit has been a source of environmental pollution for very long time. Operated through four open pits with an annual production of about 3 million tons of ore at an average grade of about 0.5% Cu, the deposit to date has produced an enormous pile of waste (exceeding 100 million tons) with tailings composed of 36 % SiO2, 39% Fe2O3 and 32% S, mainly in the form of pyrite and quartz. Waters in the vicinity of the deposit vary from high acid-acid (2.71-3.85) and high-extremely metal rich (34.48-348.12 mg/l in total) in the open pits to near neutral (6.51-7.83) and low metal (14.39-973.52 μg/l in total) in downstream environments. Despite low metal contents and near neutral pH levels of the latter, their suspended particle loads are extremely high and composed mainly of quartz and clay minerals with highly elevated levels of Fe (3.5 to 24.5% Fe2O3; 11% on average) and S (0.5 to 20.6% S; 7% on average), showing that Fe is mainly in the form of pyrite and lesser hematite. They also contain high concentrations of As, Au, Ba, Cu, Pb, and Zn. Waters collected along the course of polluted drainages are supersaturated with respect to Fe phases such as goethite, hematite, maghemite, magnetite, schwertmannite and ferrihydrite. Secondary phases such as Fe-sulphates are only found near the pits, but not along the streams due to neutral pH conditions, where pebbles are covered and cemented by Fe-oxides and hydroxides indicating that oxidation of pyrite has taken place especially at times of low water load. It follows, then, that the pyrite-rich sediment load of streams fed by the waste of the Murgul deposit is currently a big threat to the aquatic life and environment and will continue to be so even after the closure of the deposit. In fact, the oxidation will be enhanced and acidity increased due to natural conditions, which necessitates strong remedial actions to be taken.

Effects and quantification of acid runoff from sulfide-bearing rock deposited during construction of Highway E18, Norway

Science.gov (United States)

Hindar, Atle; Nordstrom, D. Kirk

2015-01-01

The Highway E18 between the cities of Grimstad and Kristiansand, southern Norway, constructed in the period 2006–2009, cuts through sulfide-bearing rock. The geology of this area is dominated by slowly-weathering gneiss and granites, and oxidation of fresh rock surfaces can result in acidification of surface water. Sulfide-containing rock waste from excavations during construction work was therefore deposited in three waste rock deposits off-site. The deposits consist of 630,000–2,360,000 metric tons of waste rock material. Shell sand and limestone gravel were added in layers in adequate amounts to mitigate initial acid runoff in one of the deposits. The shell sand addition was not adequate in the two others. The pH in the effluents from these two was reduced from 4.9–6.5 to 4.0–4.6, and Al concentrations increased from below 0.4 mg/L to 10–20 mg/L. Stream concentrations of trace metals increased by a factor of 25–400, highest for Ni, and then in decreasing order for Co, Mn, Cd, Zn and Cu. Concentrations of As, Cr and Fe remained unchanged. Ratios of Co/Ni and Cd/Zn indicate that the metal sources for these pair of metals are sphalerite and pyrite, respectively. Based on surveys and established critical limits for Al, surface waters downstream became toxic to fish and invertebrates. The sulfur release rates were remarkably stable in the monitoring period at all three sites. Annual sulfur release was 0.1–0.4% of the total amount of sulfur in the deposit, indicating release periods of 250–800 years. Precipitates of Al-hydroxysulfates, well-known from mining sites, were found at the base of the deposits, in streams and also along the ocean shore-line. The effects of added neutralization agents in the deposits and in treatment areas downstream gradually decreased, as indicated by reduced stream pH over time. Active measures are needed to avoid harmful ecological effects in the future.

Estimates of critical acid loads and exceedances for forest soils across the conterminous United States

Science.gov (United States)

Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers; Timothy J. Sullivan; Harbin Li

2007-01-01

Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A...

Multi-material poly(lactic acid) scaffold fabricated via fused deposition modeling and direct hydroxyapatite injection as spacers in laminoplasty

Science.gov (United States)

Syuhada, Ghifari; Ramahdita, Ghiska; Rahyussalim, A. J.; Whulanza, Yudan

2018-02-01

Nowadays, additive manufacturing method has been used extensively to realize any product with specific attributes rather than the conventional subtractive manufacturing method. For instance, the additive manufacturing has enable us to construct a product layer-by-layer by successively depositing several materials in one session and one platform. This paper studied the properties of a 3D printed scaffold fabricated through Poly(Lactic-acid) (PLA) deposition modelling in combination with injectable hydroxyapatite (HA)/alginate as cell carrier. The scaffold was designed to serve as a spacer in cervical laminoplasty. Therefore, a series of test were conducted to elaborate the mechanical property, porosity and in-vitro toxicity testing. The results showed that the method is reliable to fabricate the scaffold as desired although the toxicity test needs more confirmation.

Assessment of the contribution of sewer deposits to suspended solids loads in combined sewer systems during rain events.

Science.gov (United States)

Hannouche, A; Chebbo, G; Joannis, C

2014-04-01

Within the French observatories network SOERE "URBIS," databases of continuous turbidity measurements accumulating hundreds of events and many dry weather days are available for two sites with different features (Clichy in Paris and Ecully in Lyon). These measurements, converted into total suspended solids (TSS) concentration using TSS-turbidity relationships and combined with a model of runoff event mean concentration, enable the assessment of the contribution of sewer deposits to wet weather TSS loads observed at the outlet of the two watersheds. Results show that the contribution of sewer deposits to wet weather suspended solid's discharges is important but variable (between 20 and 80 % of the mass at the outlet depending on the event), including a site allegedly free of (coarse) sewer deposits. The uncertainties associated to these results are assessed too.

Piper sarmentosum is comparable to glycyrrhizic acid in reducing visceral fat deposition in adrenalectomised rats given dexamethasone.

Science.gov (United States)

Fairus, A; Ima Nirwana, S; Elvy Suhana, M R; Tan, M H; Santhana, R; Farihah, H S

2013-01-01

Visceral obesity may be due to the dysregulation of cortisol production or metabolism that lead to metabolic disease. In adipose tissue, the enzyme 11beta-hydroxysteroid dehydrogenase type 1 regulates cortisol metabolism (11beta-HSD1). A previous study showed an increase in the visceral fat deposition in adrenalectomised rats given intramuscular dexamethasone. Glycyrrhizic acid (GCA) has been shown to reduce fat deposition because it is a known potent inhibitor of the 11beta-HSD1 enzyme. Piper sarmentosum (PS) is an edible medicinal plant commonly used in Asia as traditional medicine for treating diabetes, hypertension and joint pains. In this study, we determined the effects of PS extract on the disposition and morphology of perirenal adipocytes of adrenalectomised rats given intramuscular dexamethasone. A total of 21 male Spraque Dawley rats were adrenalectomised and given intramuscular dexamethasone, 120 μg/kg/day. These rats were further divided into three groups: adrenalectomised control (ADR+Dexa; n=7), GCA-treated (ADR+Dexa+GCA; dose=240 mg/kg/day; n=7) and PS-treated (ADR+Dexa+PS; dose=125 mg/kg/day; n=7) groups. The various treatments were given via gastric gavage following 2 weeks of adrenalectomy. Treatment with PS extract for 8 weeks showed decreased deposition of perirenal adipocytes which was similar to the GCA-treated group. However, PS-treated rats had thinner adipocyte membrane compared with that of the GCA-treated group. In conclusion, PS extract decreased perirenal fat deposition and reduced the diameter of the adipocyte membrane. However, the mechanisms of action needed further study.

Estimation of aerial deposition and foliar uptake of xenobiotics: Assessment of current models

Energy Technology Data Exchange (ETDEWEB)

Link, S.O.; Fellows, R.J.; Cataldo, D.A.; Droppo, J.G.; Van Voris, P.

1987-10-01

This report reviews existing mathematical and/or computer simulation models that estimate xenobiotic deposition to and transport through (both curricular and stomatal) vegetative surfaces. The report evaluates the potential for coupling the best of those models to the existing Uptake, Translocation, Accumulation, and Biodegradation model to be used for future xenobiotic exposure assessments. Here xenobiotic compounds are defined as airborne contaminants, both organic and gaseous pollutants, that are introduced into the environment by man. Specifically this document provides a detailed review of the state-of-the-art models that addressed aerial deposition of particles and gases to foliage; foliar and cuticular transport, metabolism, and uptake of organic xenobiotics; and stomatal transport of gaseous and volatile organic xenobiotic pollutants. Where detailed information was available, parameters for each model are provided on a chemical by chemical as well as species by species basis. Sufficient detail is provided on each model to assess the potential for adapting or coupling the model to the existing UTAB plant exposure model. 126 refs., 6 figs., 10 tabs.

Systematic variations in sinter mineralogy, microtexture and diagenesis in modern siliceous hot springs: Clues for interpreting depositional conditions in ancient deposits

Science.gov (United States)

Mills, V. W.; Farmer, J. D.; Ruff, S. W.; Nunez, J.; Jahnke, L. L.

2011-12-01

The deposits of siliceous hydrothermal springs are known to capture and preserve a wide range of microbial fossil information. The recent discovery of hydrothermal silica at Home Plate, Columbia Hills, Mars has once again raised interest in the potential importance of ancient spring sinters as targets for future astrobiological mission to Mars. To create additional context information to support future in situ missions to Mars, we have documented systematic changes in the mineralogy and microtexture of modern siliceous hot spring deposits, observed along gradients in temperature, pH and flow velocity. Specific objectives are to: 1) identify chemical and physical factors that promote early diagenetic transformations of amorphous silica (opal-A), to progressively more ordered and crystalline phases (cristobalite, tridymite and quartz); 2) determine the composition and abundance of minor mineral phases, especially clays, in relationship to pH, temperature and paragenesis; and 3) to assess the usefulness of sinter mineralogy and microtexture in reconstructing the paleoenvironmental records preserved in ancient deposits. Study sites for acidic (pH 2-5) sinters included Nymph Creek, located in the Norris Geyser Basin of Yellowstone National Park (YNP). Active alkaline (pH 7-10) springs included Rabbit Creek, Steep Cone and Mound Spring located in the Lower Geyser Basin, YNP. Field measurements in active springs included pH, temperature and flow velocity, along with general microfacies assignments. To better constrain types and rates of silica diagenesis, the study also sampled older (Holocene-Pleistocene-aged) deposits. Laboratory analyses included X-ray powder diffraction (XRPD), thermal infrared spectroscopy (TIR) and thin section petrography for characterizing sinter microtextures and for placing mineral phases (identified by XRPD and TIR) into a time-ordered diagenetic framework. In analyzing the phyllosilicates present in sinters, we applied clay separation and

The Coupling Effect Research of Ash Deposition and Condensation in Low Temperature Flue Gas

Directory of Open Access Journals (Sweden)

Lei Ma

2016-01-01

Full Text Available Ash deposition is a key factor that deteriorates the heat transfer performance and leads to higher energy consumption of low pressure economizer working in low temperature flue gas. In order to study the ash deposition of heat exchange tubes in low temperature flue gas, two experiments are carried out with different types of heat exchange tubes in different flue gas environments. In this paper, Nusselt Number Nu and fouling factor ε are calculated to describe the heat transfer characteristics so as to study the ash deposition condition. The scanning electron microscope (SEM is used for the analysis of ash samples obtained from the outer wall of heat exchange tubes. The dynamic process of ash deposition is studied under different temperatures of outer wall. The results showed that ash deposition of heat exchanger will achieve a stable state in constant flue gas environment. According to the condition of condensation of acid vapor and water vapor, the process of ash deposition can be distinguished as mere ash deposition, acid-ash coupling deposition, and acid-water-ash coupling deposition.

Assessing the recovery potential of alpine moss-sedge heath: Reciprocal transplants along a nitrogen deposition gradient

International Nuclear Information System (INIS)

Armitage, Heather F.; Britton, Andrea J.; Woodin, Sarah J.; Wal, Rene van der

2011-01-01

The potential of alpine moss-sedge heath to recover from elevated nitrogen (N) deposition was assessed by transplanting Racomitrium lanuginosum shoots and vegetation turfs between 10 elevated N deposition sites (8.2-32.9 kg ha -1 yr -1 ) and a low N deposition site, Ben Wyvis (7.2 kg ha -1 yr -1 ). After two years, tissue N of Racomitrium shoots transplanted from higher N sites to Ben Wyvis only partially equilibrated to reduced N deposition whereas reciprocal transplants almost matched the tissue N of indigenous moss. Unexpectedly, moss shoot growth was stimulated at higher N deposition sites. However, moss depth and biomass increased in turfs transplanted to Ben Wyvis, apparently due to slower shoot turnover (suggested to result partly from decreased tissue C:N slowing decomposition), whilst abundance of vascular species declined. Racomitrium heath has the potential to recover from the impacts of N deposition; however, this is constrained by the persistence of enhanced moss tissue N contents. - Alpine moss-sedge heath, dominated by Racomitrium lanuginosum, from across the UK has the potential to recover from the impacts of N pollution; however, this is constrained by persistence of enhanced moss tissue N contents.

Assessing the recovery potential of alpine moss-sedge heath: Reciprocal transplants along a nitrogen deposition gradient

Energy Technology Data Exchange (ETDEWEB)

Armitage, Heather F., E-mail: h.armitage@abdn.ac.u [Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom); Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom); Britton, Andrea J. [Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom); Woodin, Sarah J. [Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom); Wal, Rene van der [Aberdeen Centre for Environmental Sustainability (ACES), School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom)

2011-01-15

The potential of alpine moss-sedge heath to recover from elevated nitrogen (N) deposition was assessed by transplanting Racomitrium lanuginosum shoots and vegetation turfs between 10 elevated N deposition sites (8.2-32.9 kg ha{sup -1} yr{sup -1}) and a low N deposition site, Ben Wyvis (7.2 kg ha{sup -1} yr{sup -1}). After two years, tissue N of Racomitrium shoots transplanted from higher N sites to Ben Wyvis only partially equilibrated to reduced N deposition whereas reciprocal transplants almost matched the tissue N of indigenous moss. Unexpectedly, moss shoot growth was stimulated at higher N deposition sites. However, moss depth and biomass increased in turfs transplanted to Ben Wyvis, apparently due to slower shoot turnover (suggested to result partly from decreased tissue C:N slowing decomposition), whilst abundance of vascular species declined. Racomitrium heath has the potential to recover from the impacts of N deposition; however, this is constrained by the persistence of enhanced moss tissue N contents. - Alpine moss-sedge heath, dominated by Racomitrium lanuginosum, from across the UK has the potential to recover from the impacts of N pollution; however, this is constrained by persistence of enhanced moss tissue N contents.

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Institute of Scientific and Technical Information of China (English)

HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

2012-01-01

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

The response of soil solution chemistry in European forests to decreasing acid deposition

DEFF Research Database (Denmark)

Johnson, James; Pannatier, Elisabeth Graf; Carnicelli, Stefano

2018-01-01

to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Altot) and dissolved organic carbon were determined for the period 1995–2012. Plots...... with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10–20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate () in soil solution; over a 10‐year period (2000...... over the entire dataset. The response of soil solution acidity was nonuniform. At 10–20 cm, ANC increased in acid‐sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid‐sensitive soils (base...

Assessment of the effectiveness of uranium deposit searching methods

International Nuclear Information System (INIS)

Suran, J.

1998-01-01

The following groups of uranium deposit searching methods are described: radiometric review of foreign work; aerial radiometric survey; automobile radiometric survey; emanation survey up to 1 m; emanation survey up to 2 m; ground radiometric survey; radiometric survey in pits; deep radiometric survey; combination of the above methods; and other methods (drilling survey). For vein-type deposits, the majority of Czech deposits were discovered in 1945-1965 by radiometric review of foreign work, automobile radiometric survey, and emanation survey up to 1 m. The first significant indications of sandstone type uranium deposits were observed in the mid-1960 by aerial radiometric survey and confirmed later by drilling. (P.A.)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.

1998-01-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.J.

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an 59 Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

1998-07-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S.J

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an {sup 59}Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Characterization of chemically deposited low-cost 2-6 thin films solar cells : modifying effects with catalytic silicotungstic acid (STA)

Energy Technology Data Exchange (ETDEWEB)

Petuenju, E.N.; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

2008-07-01

This paper described some properties of cadmium sulphide (CdS) thin films that were chemically deposited on a silicon wafer for solar cell and optoelectronic applications. The as-deposited films were thermally annealed and characterized through structural, electrical, optical, and spectroscopic methods. The modifying effects of silicotungstic acid (STA) showed promising characteristics for various applications, including X- and gamma-ray detector devices. The films were characterized by X-rays Photoelectron Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, and Photoluminescence. Ellipsometry measurements were used to determine the thickness of the sample. The study showed that there is no significant effect of the addition of 10-4 M of STA on the thickness of the film. This might be due to the low concentration of STA. No significant difference was noted for samples deposited with and without STA. In both cases the crystallite size of the sample was estimated to be lower than 1.5 microns. The CdS/Si and CdS(STA)/Si samples were annealed at 360 degrees C for 12 hours. The samples prepared with and without STA had the same structure. CdS deposited without and STA exhibited a mixed hexagonal and cubic structure, most likely because the annealing temperature of the sample was very close to the transition temperature of the cubic structure to the hexagonal structure. 3 refs., 1 tab., 3 figs.

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Hao, Shilei; Wang, Yazhou; Wang, Bochu, E-mail: wangbc2000@126.com; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-06-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro.

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

International Nuclear Information System (INIS)

Hao, Shilei; Wang, Yazhou; Wang, Bochu; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-01-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro

Structural and surface morphological studies of long chain fatty acid thin films deposited by Langmuir-Blodgett technique

Energy Technology Data Exchange (ETDEWEB)

Das, Nayan Mani, E-mail: nayanmanidas3@gmail.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Roy, Dhrubojyoti [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Gupta, Mukul [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India); Gupta, P.S. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

2012-12-15

In the present work we aim to study the structural and surface morphological characteristics of divalent cation (cadmium ion, Cd{sup 2+}) induced thin mono- to multilayer films of fatty acids such as arachidic acid and stearic acid prepared by the Langmuir-Blodgett (LB) technique. These ultra thin films of various numbers of layers were studied by X-ray diffraction (XRD), X-ray reflectivity (XRR) and Atomic Force Microscopy (AFM). In this specific Y-type deposition, it was found that as the individual layer thickness increases, the corresponding layer by layer interfacial electron density of the thin films decreases. Since the fatty acid chain tries to maintain its minimum value of cross-sectional area, tilting occurs with respect to its nearest neighbor. The tilt angle calculated for 9 layers of cadmium arachidate (CdA{sub 2}) and cadmium stearate (CdSt{sub 2}) are 18 Degree-Sign and 19.5 Degree-Sign , respectively. An asymmetric air gap of thickness {approx}3 A was also seen between the tail parts of 2 molecular chains. The RMS roughness and average height factors calculated through AFM studies show non-uniform surface morphology of both CdA{sub 2} and CdSt{sub 2}, although the calculated topographic variations were found to have more irregularity in case of CdSt{sub 2} than in case of CdA{sub 2}.

Assessing Research Data Deposits and Usage Statistics within IDEALS

Directory of Open Access Journals (Sweden)

Christie A. Wiley

2017-12-01

Full Text Available Objectives:This study follows up on previous work that began examining data deposited in an institutional repository. The work here extends the earlier study by answering the following lines of research questions: (1 What is the file composition of datasets ingested into the University of Illinois at Urbana-Champaign (UIUC campus repository? Are datasets more likely to be single-file or multiple-file items? (2 What is the usage data associated with these datasets? Which items are most popular? Methods: The dataset records collected in this study were identified by filtering item types categorized as “data” or “dataset” using the advanced search function in IDEALS. Returned search results were collected in an Excel spreadsheet to include data such as the Handle identifier, date ingested, file formats, composition code, and the download count from the item’s statistics report. The Handle identifier represents the dataset record’s persistent identifier. Composition represents codes that categorize items as single or multiple file deposits. Date available represents the date the dataset record was published in the campus repository. Download statistics were collected via a website link for each dataset record and indicates the number of times the dataset record has been downloaded. Once the data was collected, it was used to evaluate datasets deposited into IDEALS. Results: A total of 522 datasets were identified for analysis covering the period between January 2007 and August 2016. This study revealed two influxes occurring during the period of 2008-2009 and in 2014. During the first timeframe a large number of PDFs were deposited by the Illinois Department of Agriculture. Whereas, Microsoft Excel files were deposited in 2014 by the Rare Books and Manuscript Library. Single-file datasets clearly dominate the deposits in the campus repository. The total download count for all datasets was 139,663 and the average downloads per month per

Acid rain attack on outdoor sculpture in perspective

Science.gov (United States)

Livingston, Richard A.

2016-12-01

A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH - SO42- phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5-6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42- dry deposition and 23% by NO3- dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet

Low-fluorine Stockwork Molybdenite Deposits

Science.gov (United States)

Ludington, Steve; Hammarstrom, Jane; Piatak, Nadine M.

2009-01-01

Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

Reliability assessment of ultra-thin HfO2 films deposited on silicon wafer

International Nuclear Information System (INIS)

Fu, Wei-En; Chang, Chia-Wei; Chang, Yong-Qing; Yao, Chih-Kai; Liao, Jiunn-Der

2012-01-01

Highlights: ► Nano-mechanical properties on annealed ultra-thin HfO 2 film are studied. ► By AFM analysis, hardness of the crystallized HfO 2 film significantly increases. ► By nano-indention, the film hardness increases with less contact stiffness. ► Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO 2 ) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO 2 films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO 2 films deposited on silicon wafers (HfO 2 /SiO 2 /Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO 2 (nominal thickness ≈10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO 2 phases for the atomic layer deposited HfO 2 . The HfSi x O y complex formed at the interface between HfO 2 and SiO 2 /Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO 2 film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically sensitive nano-indentation. Quality assessments on as-deposited and annealed HfO 2 films can be thereafter used to estimate the mechanical properties and adhesion of ultra-thin HfO 2

Nitrogen deposition effects on Mediterranean-type ecosystems: An ecological assessment

Energy Technology Data Exchange (ETDEWEB)

Ochoa-Hueso, Raul, E-mail: raul.ochoa@ccma.csic.es [Department of Plant Physiology and Ecology, Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, C/Serrano 115 Dpdo., 28006 Madrid (Spain); Allen, Edith B. [Department of Botany and Plant Sciences and Center for Conservation Biology, University of California, Riverside, CA 92521 (United States); Branquinho, Cristina; Cruz, Cristina; Dias, Teresa [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biologia Ambiental, Campo Grande, Bloco C4, 1749-016 Lisboa (Portugal); Fenn, Mark E. [US Department of Agriculture (USDA) Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Manrique, Esteban [Department of Plant Physiology and Ecology, Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, C/Serrano 115 Dpdo., 28006 Madrid (Spain); Perez-Corona, M. Esther [Department of Ecology, Faculty of Biology, Universidad Complutense de Madrid, C/Jose Antonio Novais 2, 28040 Madrid (Spain); Sheppard, Lucy J. [Centre of Ecology and Hydrology, Bush Estate, Penicuik EH26 0QB (United Kingdom); Stock, William D. [Centre for Ecosystem Management, School of Natural Sciences, Edith Cowan University, 100 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia)

2011-10-15

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling. - Highlights: > N deposition impacts are understudied in Mediterranean ecosystems out of California. > Dry N deposition is dominant and N flushes are common after rainless periods. > Water availability and P fertility regulate ecosystem responses to N deposition. > Research is needed to determine critical loads for each region and vegetation type. - Nitrogen deposition threatens the Mediterranean regions of the world.

Nitrogen deposition effects on Mediterranean-type ecosystems: An ecological assessment

International Nuclear Information System (INIS)

Ochoa-Hueso, Raul; Allen, Edith B.; Branquinho, Cristina; Cruz, Cristina; Dias, Teresa; Fenn, Mark E.; Manrique, Esteban; Perez-Corona, M. Esther; Sheppard, Lucy J.; Stock, William D.

2011-01-01

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling. - Highlights: → N deposition impacts are understudied in Mediterranean ecosystems out of California. → Dry N deposition is dominant and N flushes are common after rainless periods. → Water availability and P fertility regulate ecosystem responses to N deposition. → Research is needed to determine critical loads for each region and vegetation type. - Nitrogen deposition threatens the Mediterranean regions of the world.

ASSESSMENT OF THE CHEMICAL POLLUTION OF THE SOIL, GROUND AND BOTTOM SEDIMENTS AT KLEN GOLD AND SILVER DEPOSIT

Directory of Open Access Journals (Sweden)

Bryukhan' Fedor Fedorovich

2012-10-01

Full Text Available Currently, prospecting and design-related works are performed prior to the upcoming launch of mining operations at Klen gold and silver deposit in Chukot Autonomous District. The anthropogenic impact of the geological exploration in this intact territory has been produced since 1984. A considerable amount of borehole drilling, prospecting, road building, and temporary housing development has been performed. The engineering research, including ecological surveys, has been completed to assess the ecological impact of upcoming exploratory and mining operations at the deposit. Assessment of the geochemical condition of the landscape constituents, including the soil, ground and bottom sediments is of special importance in terms of their engineering protection and rational management of the natural environment. The above assessments were based on the field sampling made by «Sibgeoconsulting», CJSC (Krasnoyarsk and the laboratory research made by accredited laboratories of Federal State Unitary Geological Enterprise «Urangeolograzvedka» (Irkutsk and «Krasnoyarskgeologiya» (Krasnoyarsk. The analysis of the chemical pollution of soils, ground and bottom sediments is based on the examination of 30 samples. Peculiarities of the chemical composition of samples extracted at the deposit were identified. It has been discovered that pH values of the soil vary from 5.1 to 7.3. The concentration of metal in bottom sediments exceeds its concentration in the soil by far. Almost all irregular features of the sample water in the whole territory of the deposit are caused by the anthropogenic impact. In general, the metal content in soils, ground and bottom sediments within the territory of the deposit is slightly different from the regular clarke.

Atmospheric transport and deposition of pesticides: An assessment of current knowledge

DEFF Research Database (Denmark)

Pul, W.A.J. van; Bidleman, T.F.; Brorström-Lunden, E.

1999-01-01

The current knowledge on atmospheric transport and deposition of pesticides is reviewed and discussed by a working group of experts during the Workshop on Fate of pesticides in the atmosphere; implications for risk assessment, held in Driebergen, the Netherlands, 22-24 April, 1998. In general...... in the exchange processes at the interface between air and soil/water/vegetation. In all process descriptions the uncertainty in the physicochemical properties play an important role. Particularly those in the vapour pressure, Henry's law constant and its temperature dependency. More accurate data...

Environmental Characteristics of Carbonatite and Alkaline Intrusion-related Rare Earth Element (REE) Deposits

Science.gov (United States)

Seal, R. R., II; Piatak, N. M.

2017-12-01

Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are

Deposition of acidifying compounds

International Nuclear Information System (INIS)

Fowler, D.; Cape, J.N.; Sutton, M.A.; Mourne, R.; Hargreaves, K.J.; Duyzer, J.H.; Gallagher, M.W.

1992-01-01

Inputs of acidifying compounds to terrestrial ecosystems include deposition of the gases NO 2 , NO, HNO 2 , HNO 3 , NH 3 and SO 2 and the ions NO 3- , NH 4+ , SO 4 2- and H + in precipitation, cloud droplets and particles. Recent research has identified particular ecosystems and regions in which terrestrial effects are closely linked with specific deposition processes. This review paper identifies areas in which important developments have occurred during the last five years and attempts to show which aspects of the subject are most important for policy makers. Amongst the conclusions drawn, the authors advise that current uncertainties in estimates of S and N inputs by dry deposition should be incorporated in critical load calculations, and that, in regions dominated by wet deposition, spatial resolution of total inputs should be improved to match the current scales of information on landscape sensitivity to acidic inputs. 44 refs., 9 figs

Electrical properties of polyimides containing a near-surface deposit of silver

Science.gov (United States)

Rancourt, J. D.; Porta, G. M.; Taylor, L. T.

1987-01-01

Films containing a surface or near-surface deposit of palladium, gold or copper metal as well as tin, cobalt, copper, or lithium oxides have been prepared by dissolving appropriate metal salts into poly(amide-acid)/N,N-dimethylacetamide solutions and curing the solvent cast films to temperatures up to 300 C. This preparation technique has been extended to evaluate the thermal, spectroscopic, and electrical characteristics of condensation polyimide films modified with silver nitrate. A near-surface deposit of metallic silver results but the reflective surface has high electrical resistivity (sheet resistivity) due to a polymer coating or overlayer above the metal. Details pertaining to the silver nitrate modified condensation polyimides are presented. Also, the applicability of the structural model and electrical model previously proposed for the cobalt oxide system are assessed.

Effects of acid deposition on Dutch forest ecosystems

NARCIS (Netherlands)

Vries, de W.; Leeters, E.E.J.M.; Hendriks, C.M.A.

1995-01-01

Effects of elevated sulphur and nitrogen deposition on the solution chemistry of Dutch forest soils are mainly manifested by increased aluminium concentrations, associated with increased concentrations of sulphate and nitrate. Critical aluminium/base cation ratios are often exceeded below 20 cm soil

Framework for ecological risk assessment

International Nuclear Information System (INIS)

Rodier, D.; Norton, S.

1992-02-01

Increased interest in ecological issues such as global climate change, habitat loss, acid deposition, reduced biological diversity, and the ecological impacts of pesticides and toxic chemicals prompts this U.S. Environmental Protection Agency (EPA) report, A Framework for Ecological Risk Assessment ('Framework Report'). The report describes basic elements, or a framework, for evaluating scientific information on the adverse effects of physical and chemical stressors on the environment. The framework offers starting principles and a simple structure as guidance for current ecological risk assessments and as a foundation for future EPA proposals for risk assessment guidelines

Assessment of Folic Acid Supplementation in Pregnant Women by Estimation of Serum Levels of Tetrahydrofolic Acid, Dihydrofolate Reductase, and Homocysteine

Directory of Open Access Journals (Sweden)

Manisha Naithani

2016-01-01

Full Text Available Background. Status of folic acid use in pregnant women of the hilly regions in North India was little known. This study was carried out to assess the folic acid use and estimate folate metabolites in pregnant women of this region. Materials and Methods. This cross-sectional study is comprised of 76 pregnant women, whose folic acid supplementation was assessed by a questionnaire and serum levels of homocysteine, tetrahydrofolic acid (THFA, and dihydrofolate reductase (DHFR were estimated using Enzyme Linked Immunoassays. Results. The study data revealed awareness of folic acid use during pregnancy was present in 46.1% and 23.7% were taking folic acid supplements. The study depicted that there was no statistically significant difference between serum levels of THFA and DHFR in pregnant women with and without folic acid supplements (p=0.790. Hyperhomocysteinemia was present in 15.78% of the participants. Conclusion. Less awareness about folic acid supplementation and low use of folic acid by pregnant women were observed in this region. Sufficient dietary ingestion may suffice for the escalated requirements in pregnancy, but since this cannot be ensured, hence folic acid supplementation should be made as an integral part of education and reproductive health programs for its better metabolic use, growth, and development of fetus.

Ecological ranges for the pH and NO3 of syntaxa: a new basis for the estimation of critical loads for acid and nitrogen deposition

NARCIS (Netherlands)

Wamelink, G.W.W.; Goedhart, P.W.; Malinowska, A.H.; Frissel, J.Y.; Wegman, R.M.A.; Slim, P.A.; Dobben, van H.F.

2011-01-01

Question: Can the abiotic ranges of syntaxonomic units (associations) in terms of pH and nitrate concentration be estimated and then in principle be used to estimate critical loads for acid and nitrogen deposition? Location: Europe. Methods: Using splines, abiotic ranges of syntaxonomic units were

Occurrence model for volcanogenic beryllium deposits: Chapter F in Mineral deposit models for resource assessment

Science.gov (United States)

Foley, Nora K.; Hofstra, Albert H.; Lindsey, David A.; Seal, Robert R.; Jaskula, Brian W.; Piatak, Nadine M.

2012-01-01

Current global and domestic mineral resources of beryllium (Be) for industrial uses are dominated by ores produced from deposits of the volcanogenic Be type. Beryllium deposits of this type can form where hydrothermal fluids interact with fluorine and lithophile-element (uranium, thorium, rubidium, lithium, beryllium, cesium, tantalum, rare earth elements, and tin) enriched volcanic rocks that contain a highly reactive lithic component, such as carbonate clasts. Volcanic and hypabyssal high-silica biotite-bearing topaz rhyolite constitutes the most well-recognized igneous suite associated with such Be deposits. The exemplar setting is an extensional tectonic environment, such as that characterized by the Basin and Range Province, where younger topaz-bearing igneous rock sequences overlie older dolomite, quartzite, shale, and limestone sequences. Mined deposits and related mineralized rocks at Spor Mountain, Utah, make up a unique economic deposit of volcanogenic Be having extensive production and proven and probable reserves. Proven reserves in Utah, as reported by the U.S. Geological Survey National Mineral Information Center, total about 15,900 tons of Be that are present in the mineral bertrandite (Be4Si2O7(OH)2). At the type locality for volcanogenic Be, Spor Mountain, the tuffaceous breccias and stratified tuffs that host the Be ore formed as a result of explosive volcanism that brought carbonate and other lithic fragments to the surface through vent structures that cut the underlying dolomitic Paleozoic sedimentary rock sequences. The tuffaceous sediments and lithic clasts are thought to make up phreatomagmatic base surge deposits. Hydrothermal fluids leached Be from volcanic glass in the tuff and redeposited the Be as bertrandite upon reaction of the hydrothermal fluid with carbonate clasts in lithic-rich sections of tuff. The localization of the deposits in tuff above fluorite-mineralized faults in carbonate rocks, together with isotopic evidence for the

Assessment of 210Po deposition in moss species and soil around coal-fired power plant

International Nuclear Information System (INIS)

Nita Salina Abu Bakar; Ahmad Saat

2013-01-01

In the present study, the depositions of 210 Po were assessed in the surface soil and some mosses species found in the area around coal fired power plant using radiochemical deposition and alpha spectrometry counting system. The purposes of the study were to determine activity concentrations of 210 Po in mosses and surface soil collected around coal-fired power plant in relation to trace the potential source of 210 Po and to identify most suitable moss species as a bio-indicator for 210 Po deposition. In this study, different species of mosses, Orthodontium imfractum, Campylopus serratus and Leucobryum aduncum were collected in May 2011 at the area around 15 km radius from Tanjung Bin coal-fired power plant located in Pontian, Johor. The 210 Po activity concentrations in mosses and soil varied in the range 102 ± 4 to 174 ± 8 Bq/kg dry wt. and 37 ± 2 to 184 ± 8 Bq/kg dry wt., respectively. Corresponding highest activity concentration of 210 Po observed in L. aduncum, therefore, this finding can be concluded this species was the most suitable as a bio-indicator for 210 Po deposition. On the other hand, it is clear the accumulation of 210 Po in mosses might be supplied from various sources of atmospheric deposition such as coal-fired power plant operation, industrial, plantation, agriculture and fertilizer activities, burned fuel fossil and forest; and other potential sources. Meanwhile, the main source of 210 Po in surface soil is supplied from the in situ deposition of radon decay and its daughters in the soil itself. (author)

Mechanism research on coupling effect between dew point corrosion and ash deposition

International Nuclear Information System (INIS)

Wang, Yun-Gang; Zhao, Qin-Xin; Zhang, Zhi-Xiang; Zhang, Zhi-Chao; Tao, Wen-Quan

2013-01-01

In order to study the coupling mechanism between ash deposition and dew point corrosion, five kinds of tube materials frequently used as anti-dew point corrosion materials were selected as research objects. Dew point corrosion and ash deposition experiments were performed with a new type experimental device in a Chinese thermal power plant. The microstructures of the materials and the composition of ash deposition were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS). The results showed that the ash deposition layer could be divided into non-condensation zone, the main condensation zone and the secondary condensation zone. The acid vapor condensed in the main condensation zone rather than directly on the tube wall surface. The dew point corrosion mainly is oxygen corrosion under the condition of the viscosity ash deposition, and the corrosion products are composed of the ash and acid reaction products in the outer layer, iron sulfate in the middle layer, and iron oxide in the inner layer. The innermost layer is the main corrosion layer. With the increase of the tube wall temperature, the ash deposition changes from the viscosity ash deposition to the dry loose ash deposition, the ash deposition rate decreases dramatically and dew point corrosion is alleviated efficiently. The sulfuric dew point corrosion resistance of the five test materials is as follows: 316L > ND > Corten>20G > 20 steel. -- Highlights: ► Dew point corrosion and ash deposition tests of five materials were performed. ► Acid vapor condensed in the ash deposit rather than directly on the tube surface. ► Dew point corrosion resistance is as follow: 316L > ND > Corten>20G > 20 steel. ► Dew point corrosion mainly is oxygen corrosion under viscosity ash deposition

Acid rain science and politics in Japan: a history of knowledge and action toward sustainability

Energy Technology Data Exchange (ETDEWEB)

Ken Wilkening

2004-07-01

This is a pioneering work in environmental and Asian history as well as an in-depth analysis of the influence of science on domestic and international environmental politics. The book is composed of the following chapters. Chapter 2 introduces the general set of concepts used to analyze the science-politics nexus. These concepts are employed in the remainder of the book to track and explain the relationship between science and policy related to the acid deposition problem in Japan. Chapter 3 discusses nature, culture, and the acid deposition problem in Japan. It begins with a brief introduction to the acid deposition problem in general. It continues with an overview of elements of Japan's natural environment and culture that are relevant to its acid deposition problems. This is followed by a quick sketch of the history of science in Japan, which in turn serves as a preamble for describing in the final section the environmental and acid deposition chronologies used to organize analysis of Japan's acid deposition history. The swath of history between 1868 and the present (circa 2000) is divided into five environmental eras and six acid deposition periods. Chapters 4-9 discuss in detail each of the six acid deposition periods. Chapter 10 synthesizes and summarizes what was learned in the process of analyzing Japan's acid deposition history, and draws lessons that might be applied to the challenge of creating sustainable societies in Japan, Asia, and the rest of the world. An appendix describes the present state of acid deposition science in Japan.

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

2016-06-15

The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

Boosting the performance of Pt electro-catalysts toward formic acid electro-oxidation by depositing sub-monolayer Au clusters

International Nuclear Information System (INIS)

Bi Xuanxuan; Wang Rongyue; Ding Yi

2011-01-01

Highlights: → Au decoration on Pt nanoparticles simultaneously increases the activity and stability. → Sub-monolayer Au decoration changes the reaction path and results in the activity improvement. → Increasing the Au coverage will increase the specific activity. → Proper Au coverage results in a maximum mass specific activity. - Abstract: CO poisoning is the main obstacle to the application of Pt nanoparticles as anode catalysts in direct formic acid fuel cells (DFAFCs). Significant types of Pt alloys have been investigated, which often demonstrate evidently improved catalytic performance governed by difference mechanisms. By using a well-known electrochemical technique of under potential deposition and in situ redox replacement, sub-monolayer Au clusters are deposited onto Pt nanoparticle surfaces in a highly controlled manner, generating a unique surface alloy structure. Under optimum conditions, the modified Pt nanoparticles can exhibit greatly enhanced specific activity (up to 23-fold increase) at potential of -0.2 V vs. MSE toward formic acid electro-oxidation (FAEO). Interestingly, the mass specific activity can also be improved by a factor of 2.3 at potential of -0.35 V vs. MSE although significant amount of surface Pt atoms are covered by the overlayer Au clusters. The much enhanced catalytic activity can be ascribed to a Pt surface ensemble effect, which induces change of the reaction path. Moreover, the sub-monolayer Au coating on the surface also contributes to the enhanced catalyst durability by inhibiting the Pt oxidation. These results show great potential to rationally design more active and stable nanocatalysts by modifying the Pt surface with otherwise inactive materials.

Mesocosm studies to assess acidity removal from acidic mine lakes through controlled eutrophication

International Nuclear Information System (INIS)

Fyson, A.; Nixdorf, B.; Kalin, M.; Steinberg, C.E.W.

1998-01-01

Flooded lignite pits (Tagebaurestseen) in Lusatia, Germany, are acidic (pH 2.5-4) with high concentrations of iron. Mesocosms (total volume 20 l) were set up with water and sediment from a Tagebaurestsee to assess the effects of phosphate and organic amendments under natural light and low temperature. Chemical and biological parameters were observed over a 9-month period. Phosphate rock addition resulted in sustained reduction in acidity in the water column and induced the growth of Chlamydomonas spp. (Chlorophyceae) near the water surface and Lepocinclis teres (Euglenophyceae) in a band above the sediment. Addition of potatoes to mesocosms resulted in the generation of near-anoxic conditions above the sediment, and phosphorus, ammonium and carbon (organic and inorganic) were released as the potatoes decomposed. A pH > 6 was attained with 5.1 g (dry weight) of potatoes and pH > 8 with 34 g (dry weight). In both mesocosms, more than 90% of total acidity was removed

Zinc-Nickel Codeposition in Sulfate Solution Combined Effect of Cadmium and Boric Acid

Directory of Open Access Journals (Sweden)

Y. Addi

2011-01-01

Full Text Available The combined effect of cadmium and boric acid on the electrodeposition of zinc-nickel from a sulfate has been investigated. The presence of cadmium ion decreases zinc in the deposit. In solution, cadmium inhibits the zinc ion deposition and suppresses it when deposition potential value is more negative than −1.2 V. Low concentration of CdSO4 reduces the anomalous nature of Zn-Ni deposit. Boric acid decreases current density and shifts potential discharge of nickel and hydrogen to more negative potential. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. Boric acid and cadmium.

Hydrological modeling of a watershed affected by acid mine drainage (Odiel River, SW Spain). Assessment of the pollutant contributing areas

Science.gov (United States)

Galván, L.; Olías, M.; Cánovas, C. R.; Sarmiento, A. M.; Nieto, J. M.

2016-09-01

The Odiel watershed drains materials belonging to the Iberian Pyrite Belt, where significant massive sulfide deposits have been mined historically. As a result, a huge amount of sulfide-rich wastes are deposited in the watershed, which suffer from oxidation, releasing acidic lixiviates with high sulfate and metal concentrations. In order to reliably estimate the metal loadings along the watershed a complete series of discharge and hydrochemical data are essential. A hydrological model was performed with SWAT (Soil and Water Assessment Tool) to solve the scarcity of gauge stations along the watershed. The model was calibrated and validated from daily discharge data (from 1980 to 2010) at the outlet of the watershed, river inputs into an existent reservoir, and a flow gauge station close to the northern area of the watershed. Discharge data obtained from the hydrological model, together with analytical data, allowed the estimation of the dissolved pollutant load delivered annually by the Odiel River (e.g. 9140 t of Al, 2760 t of Zn). The pollutant load is influenced strongly by the rainfall regime, and can even double during extremely rainy years. Around 50% of total pollution comes from the Riotinto Mining District, so the treatment of Riotinto lixiviates reaching the Odiel watershed would reduce the AMD (Acid Mine Drainages) in a remarkable way, improving the water quality downstream, especially in the reservoir of Alcolea, currently under construction. The information obtained in this study will allow the optimization of remediation efforts in the watershed, in order to improve its water quality.

SEM/EDS characterisation of dusty deposits in precipitation and assessment of their origin

Directory of Open Access Journals (Sweden)

Miloš Miler

2014-07-01

Full Text Available Detailed scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS analysis of dusty material in rainfall residue, deposited and collected on February 19th 2014 in Ljubljana, was carried out with the intention to characterise it according to its chemical and mineral composition and to assess its origin. The material consists of poorly sorted and sharp-edged particles of mostly very fine-grained silt and clay fractions, which is consistent with long-range aerial transport. Particles are represented by illite, chlorite and kaolinite group clay minerals, quartz, feldspars, carbonates, accessory minerals and secondary Fe-oxy-hydroxide minerals. Quantities of minerals and illite/ kaolinite ratio (4.5 correspond to dusts in rainfall residues originating from Moroccan Atlas, while chlorite/kaolinite ratio (2.8 agrees better with dust from central Libya. The element ratios Al/Si, Ca/Al, K/Ca, Mg/Al, Fe/Al and (Ca+Mg/Fe in the studied dusty deposit are in good agreement with ratios in dusts from rainfall residues originating from Morocco and northern Mauritania. This was also confirmed by the trajectories of cloud movement that caused precipitation with dusty deposit, although the back trajectory HYSPLIT simulation of air masses indicated northern Mauritania, central Niger, southern Algeria, southwestern and central Libya as the most possible source regions.

Assessment of soil acidification effects on forest growth in Sweden

International Nuclear Information System (INIS)

Sverdrup, H.; Warfvinge, P.; Nihlgaard, B.

1994-01-01

The results of mapping critical loads, areas where they have been exceeded and steady state (Ca+Mg+K)/Al ratios of soils in Sweden, has been used to assess the order of magnitude of the ecological and economic risks involved with acid deposition for Swedish forests. The results of the calculations indicate that 81% of the Swedish forested area received acid deposition in excess of the critical load at present. Under continued deposition at 1990 level, forest die-back is predicted to occur on approximately 1% of the forested area, and significant growth rate reductions are predicted for 80% of the Swedish forested area. For Sweden, growth losses in the order of 17.5 million m -3 yr -1 are predicted, equivalent to approximately 19% of current growth. Comparable losses can be predicted for other Nordic countries. The soil acidification situation is predicted to deteriorate significantly during the next 5-15 years, unless rapid emission reductions can be achieved. A minimum deposition reduction over Sweden of 95% on sulphur deposition and 30% on the N deposition in relation to 1990 level is required in order to protect 95% of the Swedish forest ecosystems from adverse effects of acidification. A minimum reduction of 60% on sulphur deposition and 30% on the N deposition is required to keep forest harvest at planned levels. 148 refs., 9 figs., 9 tabs

Co-Cu-Au deposits in metasedimentary rocks-A preliminary report

Science.gov (United States)

Slack, J.F.; Causey, J.D.; Eppinger, R.G.; Gray, J.E.; Johnson, C.A.; Lund, K.I.; Schulz, K.J.

2010-01-01

A compilation of data on global Co-Cu-Au deposits in metasedimentary rocks refines previous descriptive models for their occurrence and provides important information for mineral resource assessments and exploration programs. This compilation forms the basis for a new classification of such deposits, which is speculative at this early stage of research. As defined herein, the Co-Cu-Au deposits contain 0.1 percent or more by weight of Co in ore or mineralized rock, comprising disseminated to semi-massive Co-bearing sulfide minerals with associated Fe- and Cu-bearing sulfides, and local gold, concentrated predominantly within rift-related, siliciclastic metasedimentary rocks of Proterozoic age. Some deposits have appreciable Ag ? Bi ? W ? Ni ? Y ? rare earth elements ? U. Deposit geometry includes stratabound and stratiform layers, lenses, and veins, and (or) discordant veins and breccias. The geometry of most deposits is controlled by stratigraphic layering, folds, axial-plane cleavage, shear zones, breccias, or faults. Ore minerals are mainly cobaltite, skutterudite, glaucodot, and chalcopyrite, with minor gold, arsenopyrite, pyrite, pyrrhotite, bismuthinite, and bismuth; some deposits have appreciable tetrahedrite, uraninite, monazite, allanite, xenotime, apatite, scheelite, or molybdenite. Magnetite can be abundant in breccias, veins, or stratabound lenses within ore or surrounding country rocks. Common gangue minerals include quartz, biotite, muscovite, K-feldspar, albite, chlorite, and scapolite; many deposits contain minor to major amounts of tourmaline. Altered wall rocks generally have abundant biotite or albite. Mesoproterozoic metasedimentary successions constitute the predominant geologic setting. Felsic and (or) mafic plutons are spatially associated with many deposits and at some localities may be contemporaneous with, and involved in, ore formation. Geoenvironmental data for the Blackbird mining district in central Idaho indicate that weathering of

75 FR 72581 - Assessments, Assessment Base and Rates

Science.gov (United States)

2010-11-24

... Part III Federal Deposit Insurance Corporation 12 CFR Part 327 Assessments, Assessment Base and... Assessments, Assessment Base and Rates AGENCY: Federal Deposit Insurance Corporation. ACTION: Notice of... Consumer Protection Act regarding the definition of an institution's deposit insurance assessment base...

Inter-species and intra-annual variations of moss nitrogen utilization: Implications for nitrogen deposition assessment.

Science.gov (United States)

Dong, Yu-Ping; Liu, Xue-Yan; Sun, Xin-Chao; Song, Wei; Zheng, Xu-Dong; Li, Rui; Liu, Cong-Qiang

2017-11-01

Moss nitrogen (N) concentrations and natural 15 N abundance (δ 15 N values) have been widely employed to evaluate annual levels and major sources of atmospheric N deposition. However, different moss species and one-off sampling were often used among extant studies, it remains unclear whether moss N parameters differ with species and different samplings, which prevented more accurate assessment of N deposition via moss survey. Here concentrations, isotopic ratios of bulk carbon (C) and bulk N in natural epilithic mosses (Bryum argenteum, Eurohypnum leptothallum, Haplocladium microphyllum and Hypnum plumaeforme) were measured monthly from August 2006 to August 2007 at Guiyang, SW China. The H. plumaeforme had significantly (P < 0.05) lower bulk N concentrations and higher δ 13 C values than other species. Moss N concentrations were significantly (P < 0.05) lower in warmer months than in cooler months, while moss δ 13 C values exhibited an opposite pattern. The variance component analyses showed that different species contributed more variations of moss N concentrations and δ 13 C values than different samplings. Differently, δ 15 N values did not differ significantly between moss species, and its variance mainly reflected variations of assimilated N sources, with ammonium as the dominant contributor. These results unambiguously reveal the influence of inter-species and intra-annual variations of moss N utilization on N deposition assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental hazard assessment of a marine mine tailings deposit site and potential implications for deep-sea mining.

Science.gov (United States)

Mestre, Nélia C; Rocha, Thiago L; Canals, Miquel; Cardoso, Cátia; Danovaro, Roberto; Dell'Anno, Antonio; Gambi, Cristina; Regoli, Francesco; Sanchez-Vidal, Anna; Bebianno, Maria João

2017-09-01

Portmán Bay is a heavily contaminated area resulting from decades of metal mine tailings disposal, and is considered a suitable shallow-water analogue to investigate the potential ecotoxicological impact of deep-sea mining. Resuspension plumes were artificially created by removing the top layer of the mine tailings deposit by bottom trawling. Mussels were deployed at three sites: i) off the mine tailings deposit area; ii) on the mine tailings deposit beyond the influence from the resuspension plumes; iii) under the influence of the artificially generated resuspension plumes. Surface sediment samples were collected at the same sites for metal analysis and ecotoxicity assessment. Metal concentrations and a battery of biomarkers (oxidative stress, metal exposure, biotransformation and oxidative damage) were measured in different mussel tissues. The environmental hazard posed by the resuspension plumes was investigated by a quantitative weight of evidence (WOE) model that integrated all the data. The resuspension of sediments loaded with metal mine tails demonstrated that chemical contaminants were released by trawling subsequently inducing ecotoxicological impact in mussels' health. Considering as sediment quality guidelines (SQGs) those indicated in Spanish action level B for the disposal of dredged material at sea, the WOE model indicates that the hazard is slight off the mine tailings deposit, moderate on the mine tailings deposit without the influence from the resuspension plumes, and major under the influence of the resuspension plumes. Portmán Bay mine tailings deposit is a by-product of sulphide mining, and despite differences in environmental setting, it can reflect the potential ecotoxic effects to marine fauna from the impact of resuspension of plumes created by deep-sea mining of polymetallic sulphides. A similar approach as in this study could be applied in other areas affected by sediment resuspension and for testing future deep-sea mining sites in

A deposit model for carbonatite and peralkaline intrusion-related rare earth element deposits: Chapter J in Mineral deposit models for resource assessment

Science.gov (United States)

Verplanck, Philip L.; Van Gosen, Bradley S.; Seal, Robert R.; McCafferty, Anne E.

2014-01-01

Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. A wide variety of other commodities have been exploited from carbonatites and alkaline igneous rocks including niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other elements enriched in these deposits include manganese, strontium, tantalum, thorium, vanadium, and uranium. Carbonatite and peralkaline intrusion-related rare earth element deposits are presented together in this report because of the spatial, and potentially genetic, association between carbonatite and alkaline rocks. Although these rock types occur together at many locations, carbonatite and peralkaline intrusion-related rare earth element deposits are not generally found together.

Early diagenesis of recently deposited organic matter: A 9-yr time-series study of a flood deposit

Science.gov (United States)

Tesi, T.; Langone, L.; Goñi, M. A.; Wheatcroft, R. A.; Miserocchi, S.; Bertotti, L.

2012-04-01

In Fall 2000, the Po River (Italy) experienced a 100-yr return period flood that resulted in a 1-25 cm-thick deposit in the adjacent prodelta (10-25 m water depth). In the following years, numerous post-depositional perturbations occurred including bioturbation, reworking by waves with heights exceeding 5 m, as well as periods of extremely high and low sediment supply. Cores collected in the central prodelta after the Fall 2000 flood and over the following 9 yr, allowed characterization of the event-strata in their initial state and documentation of their subsequent evolution. Sedimentological characteristics were investigated using X-radiographs and sediment texture analyses, whereas the composition of sedimentary organic matter (OM) was studied via bulk and biomarker analyses, including organic carbon (OC), total nitrogen (TN), carbon stable isotope composition (δ13C), lignin phenols, cutin-products, p-hydroxy benzenes, benzoic acids, dicarboxylic acids, and fatty acids. The 9-yr time-series analysis indicated that roughly the lower half of the original event bed was preserved in the sediment record. Conversely, the upper half of the deposit experienced significant alterations including bioturbation, addition of new material, as well as coarsening. Comparison of the recently deposited material with 9-yr old preserved strata represented a unique natural laboratory to investigate the diagenesis of sedimentary OM in a non-steady system. Bulk data indicated that OC and TN were degraded at similar rates (loss ∼17%) whereas biomarkers exhibited a broad spectrum of reactivities (loss from ∼6% to ∼60%) indicating selective preservation during early diagenesis. Given the relevance of episodic sedimentation in several margins, this study has demonstrated the utility of event-response and time-series sampling of the seabed for understanding the early diagenesis in non-steady conditions.

[Pollution Evaluation and Risk Assessment of Heavy Metals from Atmospheric Deposition in the Parks of Nanjing].

Science.gov (United States)

Wang, Cheng; Qian, Xin; Li, Hui-ming; Sun, Yi-xuan; Wang, Jin-hua

2016-05-15

Contents of heavy metals involving As, Cd, Cr, Cu, Ni, Pb and Zn from atmospheric deposition in 10 parks of Nanjing were analyzed. The pollution level, ecological risk and health risk were evaluated using Geoaccumulation Index, Potential Ecological Risk Index and the US EPA Health Risk Assessment Model, respectively. The results showed that the pollution levels of heavy metals in Swallow Rock Park, Swallow Rock Park and Mochou Lake Park were higher than the others. Compared to other cities such as Changchun, Wuhan and Beijing, the contents of heavy metals in atmospheric deposition of parks in Nanjing were higher. The evaluation results of Geoaccumulation Index showed that Pb was at moderate pollution level, Zn and Cu were between moderate and serious levels, while Cd was between serious and extreme levels. The ecological risk level of Cd was high. The assessment results of Health Risk Assessment Model indicated that there was no non-carcinogenic risk for all the seven heavy metals. For carcinogenic risk, the risks of Cd, Cr and Ni were all negligible (Risk < 1 x 10⁻⁶), whereas As had carcinogenic risk possibility but was considered to be acceptable (10⁻⁶ < Risk < 10⁻⁴).

Sulfur accumulation and atmospherically deposited sulfate in the Lake States.

Science.gov (United States)

Mark B. David; George Z. Gernter; David F. Grigal; Lewis F. Ohmann

1989-01-01

Characterizes the mass of soil sulfur (adjusted for nitrogen), and atmospherically deposited sulfate along an acid precipitation gradient from Minnesota to Michigan. The relationship of these variables, presented graphically through contour mapping, suggests that patterns of atmospheric wet sulfate deposition are reflected in soil sulfur pools.

Deposition of inhaled uranium in Brazilian reference man

International Nuclear Information System (INIS)

Cardoso, Joaquim Carlos S.; Moraes, Jose Carlos T.B.

1996-01-01

Brazilian's morphometric and physiological parameters were selected for use in assessment of deposition of inhaled uranium. The assessment results were compared with estimates of deposition made with parameters recommended in ICRP 66. (author)

Structure Of Conduits Of The Acidic Volcanism And Related Deposits In The Paraná-Etendeka Magmatic Province, São Marcos Region, South Brazil

Science.gov (United States)

Guimarães, L. F.; De Campos, C. P.; Lima, E. F. D.; Janasi, V. A.

2015-12-01

Voluminous acidic volcanics from the Paraná-Etendeka Magmatic Province crop out in the southern part of Brazil. The conduits responsible for the feeding of this intermediate/acid volcanism are preserved and well exposed in the São Marcos region (Lima et al. 2012; Geologia USP 12:49-64). Conduits are aligned along a NW-SE trend and have thicknesses up to 1 km. These structures are often characterized by mixing between dacitic and rhyodacitic magmas, with intercalation between two major zones: 1) reddish or grayish vitrophiricdacite/rhyodacite, sub-divided in massive or vesiculated; 2) reddish or grayish vitrophiric fragmented dacite/rhyodacite composed of bubble-rich angular to rounded blocks. Such fragments commonly deform coeval to the flow. A third zone dominated by filaments depicts a chaotic stretching-and-folding process from the mixture of the acid magmas. We used classical field measurements of flow structures and recognized main flow directions in these feeder-dikes. They follow two preferential directions: NW, ranging from N272° to N 355°, and NE, varying from N20° to N85°. These directions are indicative of a transtensive fissural system, which seems to be related to conjugated fractures. Evidence of an important fragmentation process in the conduits point towards the presence of related products in this region, thus rheomorphic deposits such as those observed elsewhere (e.g. Uruguay and Namibia) are expected to occur. Possible vestiges of these deposits could be represented by restricted outcrops of lens-shaped and banded hipohyaline, occasionally bubble-rich, dacites. The presence of continuous pseudotachylitic levels, tightly folded bands with horizontal axial planes together with local deformed bubble-rich pumice-like lens could be indicative of remelting and rheomorphism of previous vulcanoclastic material. Coulees and compound (lobed) dacitic lava flows, reaching up to 5-8 meters length, occur as the uppermost deposits and correspond to the

Co-Deposition of a Hydrogel/Calcium Phosphate Hybrid Layer on 3D Printed Poly(Lactic Acid Scaffolds via Dip Coating: Towards Automated Biomaterials Fabrication

Directory of Open Access Journals (Sweden)

Matthias Schneider

2018-03-01

Full Text Available The article describes the surface modification of 3D printed poly(lactic acid (PLA scaffolds with calcium phosphate (CP/gelatin and CP/chitosan hybrid coating layers. The presence of gelatin or chitosan significantly enhances CP co-deposition and adhesion of the mineral layer on the PLA scaffolds. The hydrogel/CP coating layers are fairly thick and the mineral is a mixture of brushite, octacalcium phosphate, and hydroxyapatite. Mineral formation is uniform throughout the printed architectures and all steps (printing, hydrogel deposition, and mineralization are in principle amenable to automatization. Overall, the process reported here therefore has a high application potential for the controlled synthesis of biomimetic coatings on polymeric biomaterials.

Deposition kinetics of quantum dots and polystyrene latex nanoparticles onto alumina: role of water chemistry and particle coating.

Science.gov (United States)

Quevedo, Ivan R; Olsson, Adam L J; Tufenkji, Nathalie

2013-03-05

A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex. Deposition rates were assessed over a range of ionic strengths (IS) in simple electrolyte (KCl) and in electrolyte supplemented with two organic molecules found in natural waters; namely, humic acid and rhamnolipid. The Al2O3 collector used here is selected to be representative of oxide patches found on the surface of aquifer or filter grains. Deposition studies showed that ENP deposition rates on bare Al2O3 generally decreased with increasing salt concentration, with the exception of the polyacrylic-acid (PAA) coated CdTe QD which exhibited unique deposition behavior due to changes in the conformation of the PAA coating. QD deposition rates on bare Al2O3 were approximately 1 order of magnitude lower than those of the polystyrene latex nanoparticles, likely as a result of steric stabilization imparted by the QD surface coatings. Adsorption of humic acid or rhamnolipid on the Al2O3 surface resulted in charge reversal of the collector and subsequent reduction in the deposition rates of all ENPs. Moreover, the ratio of the two QCM-D output parameters, frequency and dissipation, revealed key structural information of the ENP-collector interface; namely, on bare Al2O3, the latex particles were rigidly attached as compared to the more loosely attached QDs. This study emphasizes the importance of considering the nature of ENP coatings as well

A seasonal nitrogen deposition budget for Rocky Mountain National Park.

Science.gov (United States)

Benedict, K B; Carrico, C M; Kreidenweis, S M; Schichtel, B; Malm, W C; Collett, J L

2013-07-01

Nitrogen deposition is a concern in many protected ecosystems around the world, yet few studies have quantified a complete reactive nitrogen deposition budget including all dry and wet, inorganic and organic compounds. Critical loads that identify the level at which nitrogen deposition negatively affects an ecosystem are often defined using incomplete reactive nitrogen budgets. Frequently only wet deposition of ammonium and nitrate are considered, despite the importance of other nitrogen deposition pathways. Recently, dry deposition pathways including particulate ammonium and nitrate and gas phase nitric acid have been added to nitrogen deposition budgets. However, other nitrogen deposition pathways, including dry deposition of ammonia and wet deposition of organic nitrogen, still are rarely included. In this study, a more complete seasonal nitrogen deposition budget was constructed based on observations during a year-long study period from November 2008 to November 2009 at a location on the east side of Rocky Mountain National Park (RMNP), Colorado, USA. Measurements included wet deposition of ammonium, nitrate, and organic nitrogen, PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 microm, nitrate, and ammonium) concentrations of ammonium, nitrate, and organic nitrogen, and atmospheric gas phase concentrations of ammonia, nitric acid, and NO2. Dry deposition fluxes were determined from measured ambient concentrations and modeled deposition velocities. Total reactive nitrogen deposition by all included pathways was found to be 3.65 kg N x ha(-1) yr(-1). Monthly deposition fluxes ranged from 0.06 to 0.54 kg N x ha(-1)yr(-1), with peak deposition in the month of July and the least deposition in December. Wet deposition of ammonium and nitrate were the two largest deposition pathways, together contributing 1.97 kg N x ha(-1)yr(-1) or 54% of the total nitrogen deposition budget for this region. The next two largest deposition pathways were wet

Spectral Unmixing Modeling of the Aristarchus Pyroclastic Deposit: Assessing the Eruptive History of Glass-Rich Regional Lunar Pyroclastic Deposits

Science.gov (United States)

Jawin, E. R.; Head, J. W., III; Cannon, K.

2017-12-01

The Aristarchus pyroclastic deposit in central Oceanus Procellarum is understood to have formed in a gas-rich explosive volcanic eruption, and has been observed to contain abundant volcanic glass. However, the interpreted color (and therefore composition) of the glass has been debated. In addition, previous analyses of the pyroclastic deposit have been performed using lower resolution data than are currently available. In this work, a nonlinear spectral unmixing model was applied to Moon Mineralogy Mapper (M3) data of the Aristarchus plateau to investigate the detailed mineralogic and crystalline nature of the Aristarchus pyroclastic deposit by using spectra of laboratory endmembers including a suite of volcanic glasses returned from the Apollo 15 and 17 missions (green, orange, black beads), as well as synthetic lunar glasses (orange, green, red, yellow). Preliminary results of the M3 unmixing model suggest that spectra of the pyroclastic deposit can be modeled by a mixture composed predominantly of a featureless endmember approximating space weathering and a smaller component of glass. The modeled spectra were most accurate with a synthetic orange glass endmember, relative to the other glasses analyzed in this work. The results confirm that there is a detectable component of glass in the Aristarchus pyroclastic deposit which may be similar to the high-Ti orange glass seen in other regional pyroclastic deposits, with only minimal contributions of other crystalline minerals. The presence of volcanic glass in the pyroclastic deposit, with the low abundance of crystalline material, would support the model that the Aristarchus pyroclastic deposit formed in a long-duration, hawaiian-style fire fountain eruption. No significant detection of devitrified black beads in the spectral modeling results (as was observed at the Apollo 17 landing site in the Taurus-Littrow pyroclastic deposit), suggests the optical density of the eruptive plume remained low throughout the

Recovery of fission products from acidic waste solutions thereof

International Nuclear Information System (INIS)

Carlin, W.W.; Darlington, W.B.; Dubois, D.W.

1975-01-01

Fission products, e.g., palladium, ruthenium and technetium, are removed from aqueous, acidic waste solutions thereof. The acidic waste solution is electrolyzed in an electrolytic cell under controlled cathodic potential conditions and technetium, ruthenium, palladium and rhodium are deposited on the cathode. Metal deposit is removed from the cathode and dissolved in acid. Acid insoluble rhodium metal is recovered, dissolved by alkali metal bisulfate fusion and purified by electrolysis. In one embodiment, the solution formed by acid dissolution of the cathode metal deposit is treated with a strong oxidizing agent and distilled to separate technetium and ruthenium (as a distillate) from palladium. Technetium is separated from ruthenium by organic solvent extraction and then recovered, e.g., as an ammonium salt. Ruthenium is disposed of as waste by-product. Palladium is recovered by electrolysis of an acid solution thereof under controlled cathodic potential conditions. Further embodiments wherein alternate metal recovery sequences are used are described. (U.S.)

Acid sulfate soils and human health--a Millennium Ecosystem Assessment.

Science.gov (United States)

Ljung, Karin; Maley, Fiona; Cook, Angus; Weinstein, Philip

2009-11-01

Acid sulfate soils have been described as the "nastiest soils on earth" because of their strong acidity, increased mobility of potentially toxic elements and limited bioavailability of nutrients. They only cover a small area of the world's total problem soils, but often have significant adverse effects on agriculture, aquaculture and the environment on a local scale. Their location often coincides with high population density areas along the coasts of many developing countries. As a result, their negative impacts on ecosystems can have serious implications to those least equipped for coping with the low crop yields and reduced water quality that can result from acid sulfate soil disturbance. The Millennium Ecosystem Assessment called on by the United Nations in 2000 emphasised the importance of ecosystems for human health and well-being. These include the service they provide as sources of food and water, through the control of pollution and disease, as well as for the cultural services ecosystems provide. While the problems related to agriculture, aquaculture and the environment have been the focus of many acid sulfate soil management efforts, the connection to human health has largely been ignored. This paper presents the potential health issues of acid sulfate soils, in relation to the ecosystem services identified in the Millennium Ecosystem Assessment. It is recognised that significant implications on food security and livelihood can result, as well as on community cohesiveness and the spread of vector-borne disease. However, the connection between these outcomes and acid sulfate soils is often not obvious and it is therefore argued that the impact of such soils on human well-being needs to be recognised in order to raise awareness among the public and decision makers, to in turn facilitate proper management and avoid potential human ill-health.

Acid rain information book. Final report

International Nuclear Information System (INIS)

1983-05-01

Acid rain is one of the most widely publicized environmental issues of the day. The potential consequences of widespread acid rain demand that the phenomenon be carefully evaluated. Review of the literature shows a rapidly growing body of knowledge, but also reveals major gaps in understanding that need to be narrowed. This document discusses aspects of the acid rain phenomenon, points out areas of uncertainty and summarizes current and projected research. The report is organized by a logical progression from sources of pollutants affecting acid rain formation to the atmospheric transport and transformation of those pollutants and finally to the deposition of acid rain, the effects of that deposition, and possible mitigative measures and regulatory options. This information is followed by a discussion of uncertainties in the understanding of the acid rain phenomenon and a description of current and proposed research by responsible government agencies and other concerned organizations

Reliability assessment of ultra-thin HfO{sub 2} films deposited on silicon wafer

Energy Technology Data Exchange (ETDEWEB)

Fu, Wei-En [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Chang, Chia-Wei [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Chang, Yong-Qing [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Yao, Chih-Kai [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Jiunn-Der, E-mail: jdliao@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2012-09-01

Highlights: Black-Right-Pointing-Pointer Nano-mechanical properties on annealed ultra-thin HfO{sub 2} film are studied. Black-Right-Pointing-Pointer By AFM analysis, hardness of the crystallized HfO{sub 2} film significantly increases. Black-Right-Pointing-Pointer By nano-indention, the film hardness increases with less contact stiffness. Black-Right-Pointing-Pointer Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO{sub 2}) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO{sub 2} films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO{sub 2} films deposited on silicon wafers (HfO{sub 2}/SiO{sub 2}/Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO{sub 2} (nominal thickness Almost-Equal-To 10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO{sub 2} phases for the atomic layer deposited HfO{sub 2}. The HfSi{sub x}O{sub y} complex formed at the interface between HfO{sub 2} and SiO{sub 2}/Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO{sub 2} film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically

Assessing Reservoir Depositional Environments to Develop and Quantify Improvements in CO₂ Storage Efficiency. A Reservoir Simulation Approach

Energy Technology Data Exchange (ETDEWEB)

Okwen, Roland [University of Illinois, Champaign, IL (United States); Frailey, Scott [University of Illinois, Champaign, IL (United States); Leetaru, Hannes [University of Illinois, Champaign, IL (United States); Moulton, Sandy [Illinois State Geological Survey, Champaign, IL (United States)

2014-09-30

The storage potential and fluid movement within formations are dependent on the unique hydraulic characteristics of their respective depositional environments. Storage efficiency (E) quantifies the potential for storage in a geologic depositional environment and is used to assess basinal or regional CO₂ storage resources. Current estimates of storage resources are calculated using common E ranges by lithology and not by depositional environment. The objectives of this project are to quantify E ranges and identify E enhancement strategies for different depositional environments via reservoir simulation studies. The depositional environments considered include deltaic, shelf clastic, shelf carbonate, fluvial deltaic, strandplain, reef, fluvial and alluvial, and turbidite. Strategies considered for enhancing E include CO₂ injection via vertical, horizontal, and deviated wells, selective completions, water production, and multi-well injection. Conceptual geologic and geocellular models of the depositional environments were developed based on data from Illinois Basin oil fields and gas storage sites. The geologic and geocellular models were generalized for use in other US sedimentary basins. An important aspect of this work is the development of conceptual geologic and geocellular models that reflect the uniqueness of each depositional environment. Different injection well completions methods were simulated to investigate methods of enhancing E in the presence of geologic heterogeneity specific to a depositional environment. Modeling scenarios included horizontal wells (length, orientation, and inclination), selective and dynamic completions, water production, and multiwell injection. A Geologic Storage Efficiency Calculator (GSECalc) was developed to calculate E from reservoir simulation output. Estimated E values were normalized to diminish their dependency on fluid relative permeability. Classifying depositional environments according to

Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating

International Nuclear Information System (INIS)

Rivolo, Paola; Nisticò, Roberto; Barone, Fabrizio; Faga, Maria Giulia; Duraccio, Donatella; Martorana, Selanna; Ricciardi, Serena; Magnacca, Giuliana

2016-01-01

In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. - Highlights: • Plasma polymerized surface functionalization of hernia-repair meshes was used to confer adhesive properties. • The stability of the adhesive coating was verified under different post-deposition conditions. • The use of AFM in F/D mode was selected to monitor the coating degradation.

Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating

Energy Technology Data Exchange (ETDEWEB)

Rivolo, Paola [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Nisticò, Roberto, E-mail: roberto.nistico@unito.it [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Barone, Fabrizio [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Faga, Maria Giulia; Duraccio, Donatella [CNR-IMAMOTER, Strada delle Cacce 73, 10135 Torino (Italy); Martorana, Selanna [Herniamesh S.r.l., Via F.lli Meliga 1/C, 10034 Chivasso (Italy); Ricciardi, Serena [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Magnacca, Giuliana [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy)

2016-08-01

In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. - Highlights: • Plasma polymerized surface functionalization of hernia-repair meshes was used to confer adhesive properties. • The stability of the adhesive coating was verified under different post-deposition conditions. • The use of AFM in F/D mode was selected to monitor the coating degradation.

Fouling deposition characteristic by variation of coal particle size and deposition temperature in DTF (Drop Tube Furnace)

Energy Technology Data Exchange (ETDEWEB)

Namkung, Hueon; Jeon, Youngshin; Kim, Hyungtaek [Ajou Univ., Suwon (Korea, Republic of). Div. of Energy Systems Research; Xu, Li-hua [IAE, Suwon (Korea, Republic of). Plant Engineering Center

2013-07-01

One of the major operation obstacles in gasification process is ash deposition phenomenon. In this investigation, experiment was carried out to examine coal fouling characteristics using a laminar DTF (Drop Tube Furnace) with variation of operating condition such as different coal size, and probe surface temperature. Four different samples of pulverized coal were injected into DTF under various conditions. The ash particles are deposited on probe by impacting and agglomerating action. Fouling grains are made of eutectic compound, which is made by reacting with acid minerals and alkali minerals, in EPMA (Electron Probe Micro-Analysis). And agglomeration area of fouling at top layer is wide more than it of middle and bottom layer. The major mineral factors of fouling phenomenon are Fe, Ca, and Mg. The deposition quantity of fouling increases with increasing particle size, high alkali mineral (Fe, Ca, and Mg) contents, and ash deposition temperature.

Trends in summer chemistry linked to productivity in lakes recovering from acid deposition in the Adirondack region of New York

Science.gov (United States)

Momen, B.; Lawrence, G.B.; Nierzwicki-Bauer, S. A.; Sutherland, J.W.; Eichler, L.W.; Harrison, J.P.; Boylen, C.W.

2006-01-01

The US Environmental Protection Agency established the Adirondack Effects Assessment Program (AEAP) to evaluate and monitor the status of biological communities in lakes in the Adirondack region of New York that have been adversely affected by acid deposition. This program includes chemical analysis of 30 lakes, sampled two to three times each summer. Results of trends analysis for lake chemistry and chlorophyll a (chlor a) are presented for 1994 to 2003, and a general comparison is made with recent results of the Adirondack Long-Term Monitoring (ALTM) Program, which included chemical analysis of all but two of these lakes (plus an additional 24 lakes) monthly, year-round for 1992-2004. Increases in pH were found in 25 of the 30 AEAP lakes (P level of P level of P level of P level of P level of P chemistry were similar to those of the ALTM Program, although decreases in SO 42- concentrations were more evident in the year-round ALTM record. Overall, the results suggest (a) a degree of chemical recovery from acidification during the summer, (b) an increase in phytoplankton productivity, and (c) a decreasing trend in NO 3- concentrations resulting from the increased productivity. ?? 2007 Springer Science+Business Media, Inc.

Model boiler studies on deposition and corrosion

International Nuclear Information System (INIS)

Balakrishnan, P.V.; McVey, E.G.

1977-09-01

Deposit formation was studied in a model boiler, with sea-water injections to simulate the in-leakage which could occur from sea-water cooled condensers. When All Volatile Treatment (AVT) was used for chemistry control the deposits consisted of the sea-water salts and corrosion products. With sodium phosphate added to the boiler water, the deposits also contained the phosphates derived from the sea-water salts. The deposits were formed in layers of differing compositions. There was no significant corrosion of the Fe-Ni-Cr alloy boiler tube under deposits, either on the open area of the tube or in crevices. However, carbon steel that formed a crevice around the tube was corroded severely when the boiler water did not contain phosphate. The observed corrosion of carbon steel was caused by the presence of acidic, highly concentrated chloride solution produced from the sea-water within the crevice. Results of theoretical calculations of the composition of the concentrated solution are presented. (author)

Recent advances in the risk assessment of melamine and cyanuric acid in animal feed

Energy Technology Data Exchange (ETDEWEB)

Dorne, Jean Lou, E-mail: jean-lou.dorne@efsa.europa.eu [Unit on Contaminants, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Doerge, Daniel R. [NCTR, Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States); Vandenbroeck, Marc [Unit on Contaminants, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Fink-Gremmels, Johanna [University of Utrecht (Netherlands); Mennes, Wim [RIVM, Bilthoven (Netherlands); Knutsen, Helle K. [Norwegian Institute of Public Health, Oslo (Norway); Vernazza, Francesco [Dietary and Chemical Monitoring, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Castle, Laurence [FERA, York (United Kingdom); Edler, Lutz [German Cancer Research Center, Heidelberg (Germany); Benford, Diane [Food Standard Agency, London (United Kingdom)

2013-08-01

Melamine can be present at low levels in food and feed mostly from its legal use as a food contact material in laminates and plastics, as a trace contaminant in nitrogen supplements used in animal feeds, and as a metabolite of the pesticide cyromazine. The mechanism of toxicity of melamine involves dose-dependent formation of crystals with either endogenous uric acid or a structural analogue of melamine, cyanuric acid, in renal tubules resulting in potential acute kidney failure. Co-exposure to melamine and cyanuric acid in livestock, fish, pets and laboratory animals shows higher toxicity compared with melamine or cyanuric acid alone. Evidence for crystal formation between melamine and other structural analogs i.e. ammelide and ammeline is limited. Illegal pet food adulterations with melamine and cyanuric acid and adulteration of milk with melamine resulted in melamine–cyanuric acid crystals, kidney damage and deaths of cats and dogs and melamine–uric acid stones, hospitalisation and deaths of children in China respectively. Following these incidents, the tolerable daily intake for melamine was re-evaluated by the U.S. Food and Drug Administration, the World Health Organisation, and the Scientific Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). This review provides an overview of toxicology, the adulteration incidents and risk assessments for melamine and its structural analogues. Particular focus is given to the recent EFSA risk assessment addressing impacts on animal and human health of background levels of melamine and structural analogues in animal feed. Recent research and future directions are discussed. - Highlights: ► Melamine in food and feed. ► Forms crystals in kidney with uric acid or cyanuric acid. ► Toxicity higher with cyanuric acid. ► Recent EFSA risk assessment. ► Animal and human health.

Recent advances in the risk assessment of melamine and cyanuric acid in animal feed

International Nuclear Information System (INIS)

Dorne, Jean Lou; Doerge, Daniel R.; Vandenbroeck, Marc; Fink-Gremmels, Johanna; Mennes, Wim; Knutsen, Helle K.; Vernazza, Francesco; Castle, Laurence; Edler, Lutz; Benford, Diane

2013-01-01

Melamine can be present at low levels in food and feed mostly from its legal use as a food contact material in laminates and plastics, as a trace contaminant in nitrogen supplements used in animal feeds, and as a metabolite of the pesticide cyromazine. The mechanism of toxicity of melamine involves dose-dependent formation of crystals with either endogenous uric acid or a structural analogue of melamine, cyanuric acid, in renal tubules resulting in potential acute kidney failure. Co-exposure to melamine and cyanuric acid in livestock, fish, pets and laboratory animals shows higher toxicity compared with melamine or cyanuric acid alone. Evidence for crystal formation between melamine and other structural analogs i.e. ammelide and ammeline is limited. Illegal pet food adulterations with melamine and cyanuric acid and adulteration of milk with melamine resulted in melamine–cyanuric acid crystals, kidney damage and deaths of cats and dogs and melamine–uric acid stones, hospitalisation and deaths of children in China respectively. Following these incidents, the tolerable daily intake for melamine was re-evaluated by the U.S. Food and Drug Administration, the World Health Organisation, and the Scientific Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). This review provides an overview of toxicology, the adulteration incidents and risk assessments for melamine and its structural analogues. Particular focus is given to the recent EFSA risk assessment addressing impacts on animal and human health of background levels of melamine and structural analogues in animal feed. Recent research and future directions are discussed. - Highlights: ► Melamine in food and feed. ► Forms crystals in kidney with uric acid or cyanuric acid. ► Toxicity higher with cyanuric acid. ► Recent EFSA risk assessment. ► Animal and human health

Climax-Type Porphyry Molybdenum Deposits

Science.gov (United States)

Ludington, Steve; Plumlee, Geoffrey S.

2009-01-01

Climax-type porphyry molybdenum deposits, as defined here, are extremely rare; thirteen deposits are known, all in western North America and ranging in age from Late Cretaceous to mainly Tertiary. They are consistently found in a postsubduction, extensional tectonic setting and are invariably associated with A-type granites that formed after peak activity of a magmatic cycle. The deposits consist of ore shells of quartz-molybdenite stockwork veins that lie above and surrounding the apices of cupola-like, highly evolved, calc-alkaline granite and subvolcanic rhyolite-porphyry bodies. These plutons are invariably enriched in fluorine (commonly >1 percent), rubidium (commonly >500 parts per million), and niobium-tantalum (Nb commonly >50 parts per million). The deposits are relatively high grade (typically 0.1-0.3 percent Mo) and may be very large (typically 100-1,000 million tons). Molybdenum, as MoS2, is the primary commodity in all known deposits. The effect on surface-water quality owing to natural influx of water or sediment from a Climax-type mineralized area can extend many kilometers downstream from the mineralized area. Waste piles composed of quartz-silica-pyrite altered rocks will likely produce acidic drainage waters. The potential exists for concentrations of fluorine or rare metals in surface water and groundwater to exceed recommended limits for human consumption near both mined and unmined Climax-type deposits.

Quantitative Mineral Resource Assessment of Copper, Molybdenum, Gold, and Silver in Undiscovered Porphyry Copper Deposits in the Andes Mountains of South America

Science.gov (United States)

Cunningham, Charles G.; Zappettini, Eduardo O.; Vivallo S., Waldo; Celada, Carlos Mario; Quispe, Jorge; Singer, Donald A.; Briskey, Joseph A.; Sutphin, David M.; Gajardo M., Mariano; Diaz, Alejandro; Portigliati, Carlos; Berger, Vladimir I.; Carrasco, Rodrigo; Schulz, Klaus J.

2008-01-01

Quantitative information on the general locations and amounts of undiscovered porphyry copper resources of the world is important to exploration managers, land-use and environmental planners, economists, and policy makers. This publication contains the results of probabilistic estimates of the amounts of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) in undiscovered porphyry copper deposits in the Andes Mountains of South America. The methodology used to make these estimates is called the 'Three-Part Form'. It was developed to explicitly express estimates of undiscovered resources and associated uncertainty in a form that allows economic analysis and is useful to decisionmakers. The three-part form of assessment includes: (1) delineation of tracts of land where the geology is permissive for porphyry copper deposits to form; (2) selection of grade and tonnage models appropriate for estimating grades and tonnages of the undiscovered porphyry copper deposits in each tract; and (3) estimation of the number of undiscovered porphyry copper deposits in each tract consistent with the grade and tonnage model. A Monte Carlo simulation computer program (EMINERS) was used to combine the probability distributions of the estimated number of undiscovered deposits, the grades, and the tonnages of the selected model to obtain the probability distributions for undiscovered metals in each tract. These distributions of grades and tonnages then can be used to conduct economic evaluations of undiscovered resources in a format usable by decisionmakers. Economic evaluations are not part of this report. The results of this assessment are presented in two principal parts. The first part identifies 26 regional tracts of land where the geology is permissive for the occurrence of undiscovered porphyry copper deposits of Phanerozoic age to a depth of 1 km below the Earth's surface. These tracts are believed to contain most of South America's undiscovered resources of copper. The

Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

International Nuclear Information System (INIS)

Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

2005-01-01

Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

Trace organic compounds in wet atmospheric deposition: an overview

Science.gov (United States)

Steinheimer, T.R.; Johnson, S.M.

1987-01-01

An overview of the occurrence of organic compounds in wet atmospheric deposition is given. Multiplicity of sources and problems associated with source identification are discussed. Available literature is reviewed by using citations from Chemical Abstracts and Water Resources Abstracts through June 1985 and includes reports published through December 1984 that summarize current knowledge. Approaches to the chemical determination of organic compounds in precipitation are examined in addition to aspects of sampling protocols. Best methods for sample collection and preparation for instrumental analysis continue to be discussed among various investigators. Automatic wet-deposition-only devices for collection and extraction are preferred. Classes of organic compounds that have been identified in precipitation include a spectrum of compounds with differing properties of acidity or basicity, polarity, and water solubility. Those compounds that have been reported in rainfall, snowfall, and ice include hydrocarbons (both aromatic and nonaromatic), chlorinated derivatives of these hydrocarbons, carbonyl compounds (both acidic and nonacidic), and carboxylic acids and esters. Formic and acetic are the most abundant organic acids present. Cloudwater, fogwater, and mist also have been collected and analyzed for organic composition.

Preliminary studies on environment assessment around Wahkyn uranium deposit, West Khasi Hills District, Meghalaya: a hydro-pedo geochemical approach

International Nuclear Information System (INIS)

Umamaheswar, K.; Sinha, K.K.; Murugan, M.G.; Balasubramani, S.; Pandey, Alok

2004-01-01

Environmental baseline study is an important step in the environmental impact assessment of the uranium deposit. It forms background for mining and milling project, on the local environment. Baseline data collection programme was initiated in the later part of 2001 after identifying sampling sites covering the Wahkyn uranium deposit. Workable size of uranium with an average grade of 0.101 % U 3 O 8 has been established in coarse to medium grained, immature, grey to dark grey feldspathic sandstone with abundant carbonaceous matter and pyrite. Systematic stream water samples in conjunction with soil and stream sediment samples were collected periodically from 20 permanent sample sites spread over 4.5 sq km, located in perennial streams draining through the Wahkyn uranium deposit area

Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent.

Science.gov (United States)

Ricci, Bárbara C; Ferreira, Carolina D; Marques, Larissa S; Martins, Sofia S; Amaral, Míriam C S

This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water.

Analyses of CsI aerosol deposition in aerosol behavior tests in WIND project

International Nuclear Information System (INIS)

Kudo, Tamotsu; Shibazaki, Hiroaki; Hidaka, Akihide

1999-01-01

The aerosol deposition tests have been performed in WIND project at JAERI to characterize the aerosol behavior. The aerosol deposition tests named WAV1-D and WAV2-D were analyzed by aerosol behavior analysis codes, JAERI's ART and SNL's VICTORIA. The comparison calculation was performed for the confirmation of the analytical capabilities of the both codes and improvement of the models in ART. The deposition mass calculated by ART was larger than that by VICTORIA. This discrepancy is caused by differences in model for FP vapor condensation onto the wall surface. In the WAV2-D test, in which boric acid was placed on the floor area of the test section prior to the deposition phase to simulate the PWR primary coolant, there was a discrepancy in deposition mass between analytical results in both codes and experimental results. The discrepancy may be caused by existence of boric acid which is not considered in the codes. (author)

Uronide Deposition Rates in the Primary Root of Zea mays1

Science.gov (United States)

Silk, Wendy Kuhn; Walker, Robert C.; Labavitch, John

1984-01-01

The spatial distribution of the rate of deposition of uronic acids in the elongation zone of Zea mays L. Crow WF9 × Mo 17 was determined using the continuity equation with experimentally determined values for uronide density and growth velocity. In spatial terms, the uronide deposition rate has a maximum of 0.4 micrograms per millimeter per hour at s = 3.5 mm (i.e., at the location 3.5 mm from the root tip) and decreases to 0.1 mg mm−1 h−1 by s = 10 mm. In terms of a material tissue element, a tissue segment located initially from s = 2.0 to s = 2.1 mm has 0.14 μg of uronic acids and increases in both length and uronic acid content until it is 0.9 mm long and has 0.7 μg of uronide when its center is at s = 10 mm. Simulations of radioactive labeling experiments show that 15 min is the appropriate time scale for pulse determinations of deposition rate profiles in a rapidly growing corn root. PMID:16663488

[Uncertainty analysis of ecological risk assessment caused by heavy-metals deposition from MSWI emission].

Science.gov (United States)

Liao, Zhi-Heng; Sun, Jia-Ren; Wu, Dui; Fan, Shao-Jia; Ren, Ming-Zhong; Lü, Jia-Yang

2014-06-01

The CALPUFF model was applied to simulate the ground-level atmospheric concentrations of Pb and Cd from municipal solid waste incineration (MSWI) plants, and the soil concentration model was used to estimate soil concentration increments after atmospheric deposition based on Monte Carlo simulation, then ecological risk assessment was conducted by the potential ecological risk index method. The results showed that the largest atmospheric concentrations of Pb and Cd were 5.59 x 109-3) microg x m(-3) and 5.57 x 10(-4) microg x m(-3), respectively, while the maxima of soil concentration incremental medium of Pb and Cd were 2.26 mg x kg(-1) and 0.21 mg x kg(-1), respectively; High risk areas were located next to the incinerators, Cd contributed the most to the ecological risk, and Pb was basically free of pollution risk; Higher ecological hazard level was predicted at the most polluted point in urban areas with a 55.30% probability, while in rural areas, the most polluted point was assessed to moderate ecological hazard level with a 72.92% probability. In addition, sensitivity analysis of calculation parameters in the soil concentration model was conducted, which showed the simulated results of urban and rural area were most sensitive to soil mix depth and dry deposition rate, respectively.

Glycolic Acid Physical Properties, Impurities, And Radiation Effects Assessment

International Nuclear Information System (INIS)

Pickenheim, B.; Bibler, N.

2010-01-01

The DWPF is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H 2 and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O 2 when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and pumping of the solution may be hindered. A

Assessment of the theory and hypotheses of the acidification of watersheds

Energy Technology Data Exchange (ETDEWEB)

Krug, E.C.

1989-04-01

This report documents and critically assesses the evolution and status of the scientific understanding of the effects of acidic deposition on surface waters. The main conclusion is that the dominant theory of surface-water acidification fails to adequately incorporate many important factors and processes that influence surface water acidity. Some of these factors and processes are not well researched or recognized as being important by most scientists in the aquatic effects research area. 258 refs., 14 figs., 23 tabs.

Thermal hazard assessment of TMCH mixed with inorganic acids

Directory of Open Access Journals (Sweden)

Yeh Chi-Tang

2018-01-01

Full Text Available 1,1-Bis(tert-butylperoxy-3,3,5-trimethylcyclohexane (TMCH is a typical peroxide with two peroxy groups that may runaway and/or explode due to mixing with inorganic acids, such as HCl, HNO3, H2SO4, or H3PO4. In this study, reactivities of TMCH mixed with the above inorganic acids were assessed by differential scanning calorimetry (DSC. Furthermore, data obtained by DSC, such as exothermic onset temperature (T0, maximum temperature (Tmax, and heat of decomposition (ΔHd could be employed to acquire thermal safety parameters. Moreover, thermal activity monitor III (TAM III was employed to investigate the thermal hazards while storing or transporting TMCH and TMCH mixed with four types of commonly used inorganic acids, here as HCl, HNO3, H2SO4, or H3PO4 under isothermal conditions. Mixing TMCH with those inorganic acids resulted in higherΔHd except H3PO4, and mixing TMCH with HCl clearly decreased T0. Therefore, the phenomena of mixing those incompatible materials with TMCH can be concluded as the worst cases in terms of contamination hazards during storage and transportation of TMCH.

Nitrogen deposition effects on Mediterranean-type ecosystems: An ecological assessment

Science.gov (United States)

R. Ochoa-Hueso; E.B. Allen; C. Branquinho; C. Cruz; T. Dias; Mark Fenn; E. Manrique; M.E. Pérez-Corona; L.J. Sheppard; W.D. Stock

2011-01-01

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N...

Techno-economic assessment of the production of bio-based chemicals from glutamic acid

NARCIS (Netherlands)

Lammens, T.M.; Gangarapu, S.; Franssen, M.C.R.; Scott, E.L.; Sanders, J.P.M.

2012-01-01

In this review, possible process steps for the production of bio-based industrial chemicals from glutamic acid are described, including a techno-economic assessment of all processes. The products under investigation were those that were shown to be synthesized from glutamic acid on lab-scale, namely

Smectite Formation in Acid Sulfate Environments on Mars

Science.gov (United States)

Peretyazhko, T. S.; Niles, P. B.; Sutter, B.; Clark, J. V.; Morris, R. V.; Ming, D. W.

2017-01-01

Phyllosilicates of the smectite group detected in Noachian and early Hesperian terrains on Mars were hypothesized to form under aqueous conditions that were globally neutral to alkaline. These pH conditions and the presence of a CO2-rich atmosphere should have been favorable for the formation of large carbonate deposits. However, large-scale carbonate deposits have not been detected on Mars. We hypothesized that smectite deposits are consistent with perhaps widespread acidic aqueous conditions that prevented carbonate precipitation. The objective of our work was to investigate smectite formation under acid sulfate conditions in order to provide insight into the possible geochemical conditions required for smectite formation on Mars. Hydrothermal batch incubation experiments were performed with Mars-analogue, glass-rich, basalt simulant in the presence of sulfuric acid of variable concentration.

Flame retardancy of polyaniline-deposited paper composites prepared via in situ polymerization.

Science.gov (United States)

Wu, Xianna; Qian, Xueren; An, Xianhui

2013-01-30

Polyaniline-deposited paper composites doped with three inorganic acids were prepared via in situ polymerization, and their flame-retardant properties were investigated. Both the conductivity and flame retardancy of the composite increased with the increase of the amount of the polyaniline deposited. The doping acid played a very key role in both the conductivity and flame retardancy of the composite. The comprehensive properties of the composite could be improved when codoped with an equimolar mixture of H(3)PO(4) and H(2)SO(4) or H(3)PO(4) and HCl. The decay of the flame retardancy of the composite in atmosphere was due to the dedoping of the polyaniline deposited on cellulose fibers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extreme nitrogen deposition can change methane oxidation rate in moist acidic tundra soil in Arctic regions

Science.gov (United States)

Lee, J.; Kim, J.; Kang, H.

2017-12-01

Recently, extreme nitrogen(N) deposition events are observed in Arctic regions where over 90% of the annual N deposition occurred in just a few days. Since Arctic ecosystems are typically N-limited, input of extremely high amount of N could substantially affect ecosystem processes. CH4 is a potent greenhouse gas that has 25 times greater global warming potential than CO2 over a 100-year time frame. Ammonium is known as an inhibitor of methane oxidation and nitrate also shows inhibitory effect on it in temperate ecosystems. However, effects of N addition on Arctic ecosystems are still elusive. We conducted a lab-scale incubation experiment with moist acidic tundra (MAT) soil from Council, Alaska to investigate the effect of extreme N deposition events on methane oxidation. Zero point five % methane was added to the head space to determine the potential methane oxidation rate of MAT soil. Three treatments (NH4NO3-AN, (NH4)2SO4-AS, KNO3-PN) were used to compare effects of ammonium, nitrate and salts. All treatments were added in 3 levels: 10μg N gd.w-1(10), 50μg N gd.w-1(50) and 100μg N gd.w-1(100). AN10 and AN50 increased methane oxidation rate 1.7, 6% respectively. However, AN100 shows -8.5% of inhibitory effect. In AS added samples, all 3 concentrations (AN10, AN50, AN100) stimulated methane oxidation rate with 4.7, 8.9, 4%, respectively. On the contrary, PN50 (-9%) and PN100 (-59.5%) exhibited a significant inhibitory effect. We also analyzed the microbial gene abundance and community structures of methane oxidizing bacteria using a DNA-based fingerprinting method (T-RFLP) Our study results suggest that NH4+ can stimulate methane oxidation in Arctic MAT soil, while NO3- can inhibit methane oxidation significantly.

Factors that influence properties of FOG deposits and their formation in sewer collection systems.

Science.gov (United States)

Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

2014-02-01

Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system. Copyright © 2013 Elsevier Ltd. All rights reserved.

Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

International Nuclear Information System (INIS)

Laudon, Hjalmar; Poleo, Antonio B.S.; Voellestad, Leif Asbjoern; Bishop, Kevin

2005-01-01

Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring

Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

Energy Technology Data Exchange (ETDEWEB)

Laudon, Hjalmar [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden)]. E-mail: hjalmar.laudon@sek.slu.se; Poleo, Antonio B.S. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Voellestad, Leif Asbjoern [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Bishop, Kevin [Department of Environmental Assessment, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden)

2005-05-01

Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring.

Transcriptome changes favoring intramuscular fat deposition in the longissimus muscle following castration of bulls.

Science.gov (United States)

Jeong, J; Bong, J; Kim, G D; Joo, S T; Lee, H-J; Baik, M

2013-10-01

Castration increases intramuscular fat (IMF) deposition, improving beef quality in cattle. The present study was performed to determine the global transcriptome changes following castration of bulls and to identify genes associated with IMF deposition in the longissimus dorsi (LM) of Korean cattle. A customized bovine CombiMatrix oligonucleotide microarray was constructed, and transcriptome changes following castration were determined by microarray hybridization. Transcriptome comparison between bulls and steers indicated that 428 of 8,407 genes were differentially expressed in the LM by greater than two fold (P castration. Castration upregulated transcription of adipogenic perilipin 2 (PLIN2) and visfatin, lipogenic fatty acid synthase, fatty acid esterification 1-acylglycerol-3-phosphate O-acyltransferase 5, and many fatty acid oxidation-related genes. Many TCA cycle and OP genes were also transcriptionally upregulated. Correlation analysis indicated that the IMF content in the LM was highly correlated with mRNA levels of PLIN2 (r = 0.70, P castration shifts transcription of lipid metabolism genes, favoring IMF deposition by increasing adipogenesis, lipogenesis, and triglyceride synthesis. This study also indicated that castration increases transcription of genes involved in fatty acid oxidation and subsequent energy production (TCA and OP genes). Our microarray analysis provided novel information that castration alters the transcriptome associated with lipid/energy metabolism, favoring IMF deposition in the LM.

Effects of chicory inulin on serum metabolites of uric acid, lipids, glucose, and abdominal fat deposition in quails induced by purine-rich diets.

Science.gov (United States)

Lin, Zhijian; Zhang, Bing; Liu, Xiaoqing; Jin, Rui; Zhu, Wenjing

2014-11-01

Inulin, a group of dietary fibers, is reported to improve the metabolic disorders. In the present study, we investigated the effects of chicory inulin on serum metabolites of uric acid (UA), lipids, glucose, and abdominal fat deposition in quail model induced by a purine-rich diet. In this study, 60 male French quails were randomly allocated to five groups: CON (control group), MOD (model group), BEN (benzbromarone-treated group), CHI-H (high-dosage chicory inulin-treated group), and CHI-L (low-dosage chicory inulin-treated group). The serum UA level was significantly increased in the model group from days 7 to 28, as well as triglyceride (TG) and free fatty acid (FFA) increased later in the experimental period. The abdominal fat ratio was increased on day 28. Benzbromarone can decrease UA levels on days 14 and 28. The high and low dosage of chicory inulin also decreased serum UA levels on days 7, 14, and 28. The abdominal fat ratio, activity, and protein of acetyl-CoA carboxylase (ACC) were decreased in chicory inulin-treated groups. The activities of xanthine oxidase (XOD) and fatty acid synthase (FAS) were increased in the model group and decreased in the benzbromarone and chicory inulin groups. This study evaluated a quail model of induced hyperuricemia with other metabolic disorders caused by a high-purine diet. The results indicated that a purine-rich diet might contribute to the development of hyperuricemia, hypertriglyceridemia, and abdominal obesity. Chicory inulin decreased serum UA, TG, and abdominal fat deposition in a quail model of hyperuricemia by altering the ACC protein expression and FAS and XOD activities.

The Development and Validation of an In Vitro Airway Model to Assess Realistic Airway Deposition and Drug Permeation Behavior of Orally Inhaled Products Across Synthetic Membranes.

Science.gov (United States)

Huynh, Bao K; Traini, Daniela; Farkas, Dale R; Longest, P Worth; Hindle, Michael; Young, Paul M

2018-04-01

Current in vitro approaches to assess lung deposition, dissolution, and cellular transport behavior of orally inhaled products (OIPs) have relied on compendial impactors to collect drug particles that are likely to deposit in the airway; however, the main drawback with this approach is that these impactors do not reflect the airway and may not necessarily represent drug deposition behavior in vivo. The aim of this article is to describe the development and method validation of a novel hybrid in vitro approach to assess drug deposition and permeation behavior in a more representative airway model. The medium-sized Virginia Commonwealth University (VCU) mouth-throat (MT) and tracheal-bronchial (TB) realistic upper airway models were used in this study as representative models of the upper airway. The TB model was modified to accommodate two Snapwell ® inserts above the first TB airway bifurcation region to collect deposited nebulized ciprofloxacin-hydrochloride (CIP-HCL) droplets as a model drug aerosol system. Permeation characteristics of deposited nebulized CIP-HCL droplets were assessed across different synthetic membranes using the Snapwell test system. The Snapwell test system demonstrated reproducible and discriminatory drug permeation profiles for already dissolved and nebulized CIP-HCL droplets through a range of synthetic permeable membranes under different test conditions. The rate and extent of drug permeation depended on the permeable membrane material used, presence of a stirrer in the receptor compartment, and, most importantly, the drug collection method. This novel hybrid in vitro approach, which incorporates a modified version of a realistic upper airway model, coupled with the Snapwell test system holds great potential to evaluate postairway deposition characteristics, such as drug permeation and particle dissolution behavior of OIPs. Future studies will expand this approach using a cell culture-based setup instead of synthetic membranes, within a

Estimating chemical composition of atmospheric deposition fluxes from mineral insoluble particles deposition collected in the western Mediterranean region

Directory of Open Access Journals (Sweden)

Y. Fu

2017-11-01

Full Text Available In order to measure the mass flux of atmospheric insoluble deposition and to constrain regional models of dust simulation, a network of automatic deposition collectors (CARAGA has been installed throughout the western Mediterranean Basin. Weekly samples of the insoluble fraction of total atmospheric deposition were collected concurrently on filters at five sites including four on western Mediterranean islands (Frioul and Corsica, France; Mallorca, Spain; and Lampedusa, Italy and one in the southern French Alps (Le Casset, and a weighing and ignition protocol was applied in order to quantify their mineral fraction. Atmospheric deposition is both a strong source of nutrients and metals for marine ecosystems in this area. However, there are few data on trace-metal deposition in the literature, since their deposition measurement is difficult to perform. In order to obtain more information from CARAGA atmospheric deposition samples, this study aimed to test their relevance in estimating elemental fluxes in addition to total mass fluxes. The elemental chemical analysis of ashed CARAGA filter samples was based on an acid digestion and an elemental analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES and mass spectrometry (MS in a clean room. The sampling and analytical protocols were tested to determine the elemental composition for mineral dust tracers (Al, Ca, K, Mg and Ti, nutrients (P and Fe and trace metals (Cd, Co, Cr, Cu, Mn, Ni, V and Zn from simulated wet deposition of dust analogues and traffic soot. The relative mass loss by dissolution in wet deposition was lower than 1 % for Al and Fe, and reached 13 % for P due to its larger solubility in water. For trace metals, this loss represented less than 3 % of the total mass concentration, except for Zn, Cu and Mn for which it could reach 10 %, especially in traffic soot. The chemical contamination during analysis was negligible for all the elements except for Cd

Hideout in steam generator tube deposits

International Nuclear Information System (INIS)

Balakrishnan, P.V.; Franklin, K.J.; Turner, C.W.

1998-05-01

Hideout in deposits on steam generator tubes was studied using tubes coated with magnetite. Hideout from sodium chloride solutions at 279 degrees C was followed using an on-line high-temperature conductivity probe, as well as by chemical analysis of solution samples from the autoclave in which the studies were done. Significant hideout was observed only at a heat flux greater than 200 kW/m 2 , corresponding to a temperature drop greater than 2 degrees C across the deposits. The concentration factor resulting from the hideout increased highly non-linearly with the heat flux (varying as high as the fourth power of the heat flux). The decrease in the apparent concentration factor with increasing deposit thickness suggested that the pores in the deposit were occupied by a mixture of steam and water, which is consistent with the conclusion from the thermal conductivity measurements on deposits in a separate study. Analyses of the deposits after the hideout tests showed no evidence of any hidden-out solute species, probably due to the concentrations being very near the detection limits and to their escape from the deposit as the tests were being ended. This study showed that hideout in deposits may concentrate solutes in the steam generator bulk water by a factor as high as 2 x 10 3 . Corrosion was evident under the deposit in some tests, with some chromium enrichment on the surface of the tube. Chromium enrichment usually indicates an acidic environment, but the mobility required of chromium to become incorporated into the thick magnetite deposit may indicate corrosion under an alkaline environment. An alkaline environment could result from preferential accumulation of sodium in the solution in the deposit during the hideout process. (author)

Effect of acids and bases on electrophoretic deposition of

Czech Academy of Sciences Publication Activity Database

Cihlář, J.; Drdlík, D.; Cihlářová, Z.; Hadraba, Hynek

2013-01-01

Roč. 33, č. 10 (2013), s. 1885-1892 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR GD106/09/H035 Institutional support: RVO:68081723 Keywords : Electrophoretic deposition * Zirconia * Alumina * 2-Propanol * Electrosteric stabilization Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.307, year: 2013

Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition.

Science.gov (United States)

Wiedermann, Magdalena M; Gunnarsson, Urban; Ericson, Lars; Nordin, Annika

2009-01-01

Here, it was investigated whether Sphagnum species have adjusted their nitrogen (N) uptake in response to the anthropogenic N deposition that has drastically altered N-limited ecosystems, including peatlands, worldwide. A lawn species, Sphagnum balticum, and a hummock species, Sphagnum fuscum, were collected from three peatlands along a gradient of N deposition (2, 8 and 12 kg N ha(-1) yr(-1)). The mosses were subjected to solutions containing a mixture of four N forms. In each solution one of these N forms was labeled with (15)N (namely (15)NH(+)(4), (15)NO(-)(3) and the amino acids [(15)N]alanine (Ala) and [(15)N]glutamic acid (Glu)). It was found that for both species most of the N taken up was from , followed by Ala, Glu, and very small amounts from NO(-)(3). At the highest N deposition site N uptake was reduced, but this did not prevent N accumulation as free amino acids in the Sphagnum tissues. The reduced N uptake may have been genetically selected for under the relatively short period with elevated N exposure from anthropogenic sources, or may have been the result of plasticity in the Sphagnum physiological response. The negligible Sphagnum NO(-)(3) uptake may make any NO(-)(3) deposited readily available to co-occurring vascular plants.

Use of derivatives to assess preservation of hydrocarbon deposits

Science.gov (United States)

Koshkin, K. A.; Melkishev, O. A.

2018-05-01

The paper considers the calculation of derivatives along the surface of a modern and paleostructure map of a Tl2-b formation top used to forecast the preservation of oil and gas deposits in traps according to 3D seismic survey via statistical methods. It also suggests a method to evaluate morphological changes of the formation top by calculating the difference between derivatives. The proposed method allows analyzing structural changes of the formation top in time towards primary migration of hydrocarbons. The comprehensive use of calculated indicators allowed ranking the prepared structures in terms of preservation of hydrocarbon deposits.

Hydrogeological assessment of Acid mine Drainage impacts in the West Rand Basin, Gauteng Province

CSIR Research Space (South Africa)

Hobbs, PJ

2007-08-01

Full Text Available HYDROGEOLOGICAL ASSESSMENT OF ACID MINE DRAINAGE IMPACTS IN THE WEST RAND BASIN, GAUTENG PROVINCE Principal Author PJ Hobbs (Pr.Sci.Nat.) Co-author JE Cobbing (Pr.Sci.Nat.) August 2007 Report prepared for CSIR / THRIP Document... it is published. A Hydrogeological Assessment of Acid Mine Drainage Report No. Impacts in the West Rand Basin, Gauteng Province CSIR/NRE/WR/ER/2007/0097/C CSIR Natural Resources and the Environment (i) The “Lodge” spring rising...

A New Occurrence Model for National Assessment of Undiscovered Volcanogenic Massive Sulfide Deposits

Science.gov (United States)

Shanks, W.C. Pat; Dusel-Bacon, Cynthia; Koski, Randolph; Morgan, Lisa A.; Mosier, Dan; Piatak, Nadine M.; Ridley, Ian; Seal, Robert R.; Schulz, Klaus J.; Slack, John F.; Thurston, Roland

2009-01-01

Volcanogenic massive sulfide (VMS) deposits are very significant current and historical resources of Cu-Pb-Zn-Au-Ag, are active exploration targets in several areas of the United States and potentially have significant environmental effects. This new USGS VMS deposit model provides a comprehensive review of deposit occurrence and ore genesis, and fully integrates recent advances in the understanding of active seafloor VMS-forming environments, and integrates consideration of geoenvironmental consequences of mining VMS deposits. Because VMS deposits exhibit a broad range of geological and geochemical characteristics, a suitable classification system is required to incorporate these variations into the mineral deposit model. We classify VMS deposits based on compositional variations in volcanic and sedimentary host rocks. The advantage of the classification method is that it provides a closer linkage between tectonic setting and lithostratigraphic assemblages, and an increased predictive capability during field-based studies.

A geochemical characterization of cold-water natural acid rock drainage at the Zn–Pb XY deposit, Yukon, Canada

International Nuclear Information System (INIS)

Gault, Kristen B.; Gammon, Paul; Fortin, Danielle

2015-01-01

Highlights: • Characterizes the waters and minerals of a natural acid rock drainage (ARD). • Demonstrates that cold climate ARD is mostly similar to temperate systems. • Cold-climate differences impact kinetic rates and hydrologic seasonality. • Demonstrates that thermodynamic equilibrium governs the ARD system. • Demonstrates that extraneous inputs can be detected in the system. - Abstract: Acid rock drainage (ARD) is considered to be temperature-limited due to the diminished activity of Fe(II)-oxidizing microbes at low temperatures. Nonetheless, ARD streams are present in cold climates. This study presents a geochemical characterization of a cold climate ARD creek at the Zn–Pb XY deposit in Yukon, Canada, which showed highly elevated concentrations of dissolved zinc (up to 475 mg/L). Acid rock drainage at the XY deposit is likely generated via subsurface abiotic and biotic oxidation of sulfide minerals, and then exits as seeps at the headwaters of the creek. The uppermost reaches of the creek have the lowest pH levels (pH 3.3) and highest metal concentrations, with prolific precipitation of iron-hydroxysulfate and -oxyhydroxide mineral precipitates (schwertmannite, jarosite, and goethite), present as terraced iron formations (TIFs) at one sampling location. The lower reaches of the creek show a progressive pH increase (up to pH level 4.9) which occurs due to Fe(III)- and Al-hydrolysis, the neutralizing influence of carbonate-rich strata and/or ground waters, and dilution by surface waters entering the creek. Progressive pH neutralization causes a change in precipitate mineralogy to X-ray amorphous Al-hydroxysulfates, with a composition similar to aluminite and hydrobasaluminite, and amorphous Al(OH)_3. Natural attenuation of Cd, Zn, and Pb occurred downstream from the headwater seeps, which was likely influenced by adsorption reactions involving both metal-sulfate anions and metal-sulfate ternary complexes. Generally, the concentrations of Cd, Zn, and

Analysis of tellurium thin films electrodeposition from acidic citric bath

Energy Technology Data Exchange (ETDEWEB)

Kowalik, Remigiusz; Kutyła, Dawid [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Mech, Krzysztof [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, al. A. Mickiewicza 30, Krakow (Poland); Żabiński, Piotr, E-mail: rkowalik@agh.edu.pl [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland)

2016-12-01

This work presents the description of the electrochemical process of formation thin tellurium layers from citrate acidic solution. The suggested methodology consists in the preparation of stable acidic baths with high content of tellurium, and with the addition of citrate acid. In order to analyse the mechanism of the process of tellurium deposition, the electroanalytical tests were conducted. The tests of cyclic voltammetry and hydrodynamic ones were performed with the use of polycrystalline gold disk electrode. The range of potentials in which deposition of tellurium in direct four-electron process is possible was determined as well as the reduction of deposited Te° to Te{sup 2−} and its re-deposition as a result of the comproportionation reaction. On the basis of the obtained results, the deposition of tellurium was conducted by the potentiostatic method. The influence of a deposition potential and a concentration of TeO{sub 2} in the solution on the rate of tellurium coatings deposition was examined. The presence of tellurium was confirmed by X-ray spectrofluorometry and electron probe microanalysis. In order to determine the phase composition and the morphology, the obtained coatings were analysed with the use of x-ray diffraction and scanning electron microscopy.

Enriching acid rock drainage related microbial communities from surface-deposited oil sands tailings.

Science.gov (United States)

Dean, Courtney; Xiao, Yeyuan; Roberts, Deborah J

2016-10-01

Little is known about the microbial communities native to surface-deposited pyritic oil sands tailings, an environment where acid rock drainage (ARD) could occur. The goal of this study was to enrich sulfur-oxidizing organisms from these tailings and determine whether different populations exist at pH levels 7, 4.5, and 2.5. Using growth-based methods provides model organisms for use in the future to predict potential activities and limitations of these organisms and to develop possible control methods. Thiosulfate-fed enrichment cultures were monitored for approximately 1 year. The results showed that the enrichments at pH 4.5 and 7 were established quicker than at pH 2.5. Different microbial community structures were found among the 3 pH environments. The sulfur-oxidizing microorganisms identified were most closely related to Halothiobacillus neapolitanus, Achromobacter spp., and Curtobacterium spp. While microorganisms related to Chitinophagaceae and Acidocella spp. were identified as the only possible iron-oxidizing and -reducing microbes. These results contribute to the general knowledge of the relatively understudied microbial communities that exist in pyritic oil sands tailings and indicate these communities may have a potential role in ARD generation, which may have implications for future tailings management.

Uranium deposit research, 1983

International Nuclear Information System (INIS)

Ruzicka, V.; LeCheminant, G.M.

1984-01-01

Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

Certified reference materials - beech leaves and spruce needles - for the quality control in monitoring damage in forests by acid deposition

Energy Technology Data Exchange (ETDEWEB)

Maier, E A; Griepink, B [Commission of the European Communities, Brussels (Belgium). Community Bureau of Reference; Muntau, H [Commission of the European Communities, Ispra (Italy). Joint Research Centre

1989-12-01

The chemical determination of various elements in leaves or needles allows to establish the damage caused by acid deposition. To control the quality of such determinations the Community Bureau of Reference (BCR) produced two Certified Reference Materials: Beech leaves (CRM No. 100) and Spruce needles (CRM No. 101). After a careful preparation procedure, a homogeneity study and a long term stability study, the materials were certified for: Cl, N, P and S in CRM No. 100, Al, Ca, Cl, Mg, Mn, N, P, S and Zn in CRM No. 101. Indicative values on the content of 19 majors and trace elements are also reported. (orig.).

Dissolution of synthetic uranium dibutyl phosphate deposits in oxidizing and reducing chemical formulations

International Nuclear Information System (INIS)

Rufus, A.L.; Sathyaseelan, V.S.; Narasimhan, S.V.; Velmurugan, S.

2013-01-01

Graphical abstract: SEM of the U-DBP coated stainless steel coupon before and after exposure to chemical formulation containing acid permanganate at 80 °C. -- Highlights: •Combination of oxidation and reduction processes efficiently dissolves U-DBP deposits. •NP and NAC formulations are compatible with SS-304. •Dissolved uranium and added chemicals are effectively removed via ion exchangers. -- Abstract: Permanganate and nitrilotriacetic acid (NTA) based dilute chemical formulations were evaluated for the dissolution of uranium dibutyl phosphate (U-DBP), a compound that deposits over the surfaces of nuclear reprocessing plants and waste storage tanks. A combination of an acidic, oxidizing treatment (nitric acid with permanganate) followed by reducing treatment (NTA based formulation) efficiently dissolved the U-DBP deposits. The dissolution isotherm of U-DBP in its as precipitated form followed a logarithmic fit. The same chemical treatment was also effective in dissolving U-DBP coated on the surface of 304-stainless steel, while resulting in minimal corrosion of the stainless steel substrate material. Investigation of uranium recovery from the resulting decontamination solutions by ion exchange with a bed of mixed anion and cation resins showed quantitative removal of uranium

Dissolution of synthetic uranium dibutyl phosphate deposits in oxidizing and reducing chemical formulations

Energy Technology Data Exchange (ETDEWEB)

Rufus, A.L.; Sathyaseelan, V.S.; Narasimhan, S.V.; Velmurugan, S., E-mail: svelu@igcar.gov.in

2013-06-15

Graphical abstract: SEM of the U-DBP coated stainless steel coupon before and after exposure to chemical formulation containing acid permanganate at 80 °C. -- Highlights: •Combination of oxidation and reduction processes efficiently dissolves U-DBP deposits. •NP and NAC formulations are compatible with SS-304. •Dissolved uranium and added chemicals are effectively removed via ion exchangers. -- Abstract: Permanganate and nitrilotriacetic acid (NTA) based dilute chemical formulations were evaluated for the dissolution of uranium dibutyl phosphate (U-DBP), a compound that deposits over the surfaces of nuclear reprocessing plants and waste storage tanks. A combination of an acidic, oxidizing treatment (nitric acid with permanganate) followed by reducing treatment (NTA based formulation) efficiently dissolved the U-DBP deposits. The dissolution isotherm of U-DBP in its as precipitated form followed a logarithmic fit. The same chemical treatment was also effective in dissolving U-DBP coated on the surface of 304-stainless steel, while resulting in minimal corrosion of the stainless steel substrate material. Investigation of uranium recovery from the resulting decontamination solutions by ion exchange with a bed of mixed anion and cation resins showed quantitative removal of uranium.

Soil N chemistry in oak forests along a nitrogen deposition gradient

DEFF Research Database (Denmark)

Nilsson, Lars Ola; Wallander, Håkan; Bååth, Erland

2006-01-01

values of grass and uppermost soil layers indicate increased nitrification rates in high N deposition sites, but no large downward movements of NO3 in these soils. Only a few sites had NO-3 concentrations exceeding 1 mg N l-¹ in soil solution at 50 cm depth, which showed that N deposition to these acid...

Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts

NARCIS (Netherlands)

Phoenix, G.K.; Hicks, W.K.; Cinderby, S.; Kuylenstierna, J.C.I.; Stock, W.D.; Dentener, F.J.; Giller, K.E.; Austin, A.T.; Lefroy, R.D.B.; Gimeno, B.S.; Ashmore, M.R.; Ineson, P.

2006-01-01

Increased atmospheric nitrogen (N) deposition is known to reduce plant diversity in natural and semi-natural ecosystems, yet our understanding of these impacts comes almost entirely from studies in northern Europe and North America. Currently, we lack an understanding of the threat of N deposition

Surface interactions of cesium and boric acid with stainless steel

International Nuclear Information System (INIS)

Grossman-Canfield, N.

1995-08-01

In this report, the effects of cesium hydroxide and boric acid on oxidized stainless steel surfaces at high temperatures and near one atmosphere of pressure are investigated. This is the first experimental investigation of this chemical system. The experimental investigations were performed using a mass spectrometer and a mass electrobalance. Surfaces from the different experiments were examined using a scanning electron microscope to identify the presence of deposited species, and electron spectroscopy for chemical analysis to identify the species deposited on the surface. A better understanding of the equilibrium thermodynamics, the kinetics of the steam-accelerated volatilizations, and the release kinetics are gained by these experiments. The release rate is characterized by bulk vaporization/gas-phase mass transfer data. The analysis couples vaporization, deposition, and desorption of the compounds formed by cesium hydroxide and boric acid under conditions similar to what is expected during certain nuclear reactor accidents. This study shows that cesium deposits on an oxidized stainless steel surface at temperatures between 1000 and 1200 Kelvin. Cesium also deposits on stainless steel surfaces coated with boric oxide in the same temperature ranges. The mechanism for cesium deposition onto the oxide layer was found to involve the chemical reaction between cesium and chromate. Some revaporization in the cesium hydroxide-boric acid system was observed. It has been found that under the conditions given, boric acid will react with cesium hydroxide to form cesium metaborate. A model is proposed for this chemical reaction

Understanding the spatial formation and accumulation of fats, oils and grease deposits in the sewer collection system.

Science.gov (United States)

Dominic, Christopher Cyril Sandeep; Szakasits, Megan; Dean, Lisa O; Ducoste, Joel J

2013-01-01

Sanitary sewer overflows are caused by the accumulation of insoluble calcium salts of fatty acids, which are formed by the reaction between fats, oils and grease (FOG) and calcium found in wastewaters. Different sewer structural configurations (i.e., manholes, pipes, wet wells), which vary spatially, along with other obstructions (roots intrusion) and pipe deformations (pipe sags), may influence the detrimental buildup of FOG deposits. The purpose of this study was to quantify the spatial variation in FOG deposit formation and accumulation in a pilot-scale sewer collection system. The pilot system contained straight pipes, manholes, roots intrusion, and a pipe sag. Calcium and oil were injected into the system and operated at alkaline (pH = 10) and neutral (pH = 7) pH conditions. Results showed that solid accumulations were slightly higher at neutral pH. Fourier transform infrared (FTIR) analysis on the solids samples confirmed that the solids were indeed calcium-based fatty acid salts. However, the fatty acid profiles of the solids deviated from the profile found from FOG deposits in sewer systems, which were primarily saturated fatty acids. These results confirm the work done previously by researchers and suggest an alternative fate of unsaturated fatty acids that does not lead to their incorporation in FOG deposits in full-scale sewer systems.

A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

Science.gov (United States)

Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

2013-01-01

This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

International Nuclear Information System (INIS)

Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M.A.; Nistal, A.; Rubio, J.

2016-01-01

Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO_3/H_2SO_4 reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

External radiation assessment in a wet phosphoric acid production plant

Energy Technology Data Exchange (ETDEWEB)

Bolivar, J.P.; Perez-Moreno, J.P. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Mas, J.L. [Dept. Fisica Aplicada I, Escuela Universitaria Politecnica, Universidad de Sevilla, 41012 Sevilla (Spain)], E-mail: ppmasb@us.es; Martin, J.E.; San Miguel, E.G. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Garcia-Tenorio, R. [Dept. Fisica Aplicada II, Escuela Tecnica Superior de Arquitectura, Universidad de Sevilla, 41012 Sevilla (Spain)

2009-10-15

The factories dedicated to the production of phosphoric acid by the so-called wet acid method are usually considered typical NORM industries, because the phosphate rock used as raw material usually contains high concentrations of {sup 238}U-series radionuclides. The magnitude and behaviour of the radionuclides involved in the production process revealed the need to determine its dosimetric impact on workers. This work aims to partially compensate this lack of knowledge through the determination of external effective dose rates at different zones in the process at a typical plant located in the southwest of Spain. To this end, two dosimetric sampling campaigns have been carried out at this phosphoric acid production plant. The first sampling was carried out when phosphate rocks originating in Morocco were processed, and the second one when phosphate rock processed came from the Kola Peninsula (Russia Federation). This differentiation was necessary because the activity concentrations are almost one order of magnitude higher in Moroccan phosphate rock than in Kola phosphate rock. The results obtained have reflected external dose rate enhancements as high as 1.4 {mu}Sv h{sup -1} (i.e., up to thirty times the external exposition due to radionuclides in unperturbed soils) at several points in the facility, particularly where the digested rock (pulp) is filtered. However, the most problematic points are characterised by a small occupation factor. That means that the increment in the annual effective external gamma dose received by the most-exposed worker is clearly below 1 mSv (European Commission limit for the general population) under normal production. Nevertheless, special care in the design and schedule of cleaning and maintaining work in the areas with high doses should be taken in order to avoid any possibility of exceeding the previously mentioned general population limit. In addition, the results of the dosimetric campaign showed no clear correlation between {sup

Comparative study of tantalum deposition by chemical vapor deposition and electron beam vacuum evaporation

International Nuclear Information System (INIS)

Spitz, J.; Chevallier, J.

1975-01-01

The coating by tantalum of steel parts has been carried out by the two following methods: chemical vapor deposition by hydrogen reduction of TaCl 5 (temperature=1100 deg C, pressure=200 mmHg, H 2 /TaCl 5 =10); electron beam vacuum evaporation. In this case Ta was firstly condensed by ion plating (P(Ar)=5x10 -3 up to 2x10 -2 mmHg; U(c)=3 to -4kV and J(c)=0.2 to 1mAcm -2 ) in order to ensure a good adhesion between deposit and substrate; then by vacuum condensation (substrate temperature: 300 to 650 deg C) to ensure that the coating is impervious to HCl an H 2 SO 4 acids. The advantages and inconveniences of each method are discussed [fr

Deposition pattern and throughfall fluxes in secondary cool temperate forest, South Korea

Science.gov (United States)

Kumar Gautam, Mukesh; Lee, Kwang-Sik; Song, Byeong-Yeol

2017-07-01

Chemistry and deposition fluxes in the rainfall and throughfall of red pine (Pinus densiflora), black locust (Robinia pseudoacacia), and chestnut (Castanea crenata) monocultures, and mixed red pine-black locust-chestnut stands were examined in a nutrient-limited cool temperate forest of central South Korea. Throughfall was enriched in both basic and acidic constituents relative to rainfall, suggesting that both dry deposition and canopy leaching are important sources of throughfall constituents. Net throughfall fluxes (NTFs) of cations and anions significantly differed among four different stands as well as seasonally. Red pine exhibited highest fluxes (TF and NTF) for Ca2+, black locust for K+, mixed stands for Mg2+, and chestnut for Na+. In contrast, NTF of SO42-, NO3-, and NH4+was highest in the red pine, intermediate in the chestnut and mixed stands, and lowest in the black locust. In general, canopy uptake of H+ and NH4+ for all stands was higher in summer than in winter. Dry deposition appears to play a major role in atmospheric deposition to this cool temperate forest, especially in summer. Dry deposition for both cations and anions displayed high spatial variability, even though stands were adjacent to one another and experienced identical atmospheric deposition loads. Canopy leaching of K+ (95-78% of NTF), Mg2+ (92-23% of NTF), and Ca2+ (91-12% of NTF) was highest for the black locust, lowest for chestnut, and intermediate for the red pine and mixed stands. The present study documented significant changes in throughfall chemistry and NTF among different forest stands, which presumably be related with the differences in the canopy characteristics and differences in their scavenging capacity for dry deposition and canopy exchange. Difference in the canopy retention of H+ and base cation leaching suggests that canopy exchange was mainly driven by weak acid excretion and lesser by H+ exchange reaction. Our results indicate that despite a high base cation

Assessment of folic acid and DNA damage in cleft lip and cleft palate

Directory of Open Access Journals (Sweden)

Sivakumar Brooklyin

2014-03-01

Full Text Available Studies have identified the risk factors like folic acid deficiency during gestational period, family history for orofacial clefts, drugs like antiepileptic, vitamin A. But, the data regarding the folic acid status in children with cleft lip/palate is hardly evaluated in depth. Here, an assessment of folic acid and DNA damage were carried out in children with orofacial anomalies. Folic acid level and DNA damage were evaluated by folic acid assay (direct chemiluminescent technology and single cell gel electrophoresis or comet assay method respectively. The mean value of plasma folic acid by direct chemiluminescent technology was 6.5±3.6 nmol/L and the normal value in children ranges from 11.3 to 47.6 nmol/L. The amount of damaged DNA, measured as the tail length of the comet in cases, was 19.4±8.9 ?m and the mean percentage of DNA in tail was 16.5±3.7. Folic acid deficiency could be the reason for DNA damage.

Hydrochemical uranium mining at the Straz ore deposit and its hydrogeological consequences

International Nuclear Information System (INIS)

Hanzlik, J.; Moravec, J.; Macak, P.

1992-01-01

The uranium ore deposit at Straz is situated in the North Bohemian Cretaceous Massif. Uranium is extracted from the deposit by underground chemical leaching by means of drills from the ground. Relevant to this kind of extraction, from the hydrogeological and environmental aspects, are the hydrogeological location of the deposit, the kind and amounts of the leaching solution and ways of its injection. The following amounts, in thousand tons, have been injected underground throughout the entire period of practicing chemical extraction of uranium (till 1990): sulfuric acid 3700, nitric acid 270, ammonia 100, hydrofluoric acid 25. The overall area of the leaching fields is 630 hectares, which accommodate 9300 technological boreholes. The environmental burden of the Cenomanian rocks and Turonian water reservoir was analyzed, and significantly elevated heavy metal contents from the recirculation of the technological solutions were found. The solutions expand beyond the leaching fields, causing a contamination of underground water within wider surroundings. The volume of contaminated water in the Turonian reservoir is currently estimated at 2 - 20 million m 3 . Uranium extraction by leaching is harmful at this deposit, having far-reaching impacts on the hydrosphere and ecosystem (increased dust, deforestation of slopes of the Ralsko hill, contamination of water and soil, etc.). Abandoning the ore extraction appears to be the sole feasible approach to this problem. (Z.S.). 2 tabs., 3 figs

Regional air-quality and acid-deposition modeling and the role for visualization

International Nuclear Information System (INIS)

Novak, J.H.; Dennis, R.L.

1991-11-01

The U.S. Environmental Protection Agency (EPA) uses air quality and deposition models to advance the scientific understanding of basic physical and chemical processes related to air pollution, and to assess the effectiveness of alternative emissions control strategies. The paper provides a brief technical description of several regional scale atmospheric models, their current use within EPA, and related data analysis issues. Spatial analysis is a key component in the evaluation and interpretation of the model predictions. Thus, the authors highlight several types of analysis enhancements focusing on those related to issues of spatial scale, user access to models and analysis tools, and consolidation of air quality modeling and graphical analysis capabilities. They discuss their initial experience with a Geographical Information System (GIS) pilot project that generated the initial concepts for the design of an integrated modeling and analysis environment. And finally, they present current plans to evolve this modeling/visualization approach to a distributed, heterogeneous computing environment which enables any research scientist or policy analyst to use high performance visualization techniques from his/her desktop

Characteristics of Wet Deposition in Japan

Science.gov (United States)

Iwasaki, A.; Arakaki, T.

2017-12-01

Acid deposition survey in Japan has started since 1991 by Japan Environmental Laboratories Association (JELA). The JELA has about 60 monitoring sites for wet deposition including remote, rural and urban area. The measured constituents of wet deposition are; precipitation, pH, electric conductivity, major Anions, and major Cations. From those data, we analyze spatial and temporal variations of wet deposition components in Japan. Among the 60 monitoring sites, 39 sampling sites were selected in this study, which have kept sampling continuously between 2003JFY and 2014JFY. All samples were collected by wet-only samplers. To analyze area characteristics, all the areas were divided into 6 regions; Northern part of Japan (NJ), Facing the Japan Sea (JS), Eastern part of Japan (EJ), Central part of Japan (CJ), Western part of Japan (WJ) and Southern West Islands (SW). NO3- and non-sea-salt-SO42- (nss-SO42-) are major components of rain acidification. Especially, between December and February (winter) the air mass from west affected the temporal variations of those acid components and the concentrations were higher in JS and WJ regions than those in other regions. Japanese ministry of the Environment reported that mixing ratio of NO2 in Japan has been less than 0.04ppm since 1976, and that of SO2 has been less than 0.02ppm since 1978. Their concentrations in Japan have remained flat or slowly decreased recently. However the temporal variations of NO3-/nss-SO42- ratio in winter in JS region were significantly increased on average at 2.2% y-1 from 2003JFY to 2014JFY. The results suggest that long-range transboundary air pollutants increased NO3- concentrations and NO3-/nss-SO42- ratio.

Management of polluted deposit in lake and river

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Hee; Kim, Eun Jung [Korea Environment Institute, Seoul (Korea)

1998-12-01

In this study, the perception and problem of polluted deposit in Korea, which does not have a clear concept of it, were analyzed and the need of a comprehensive polluted deposit management, including the present condition of pollution, assessment, pollution prevention, and disposal of polluted deposit, was presented. Based on the analysis on foreign management system, the framework of polluted deposit management in Korea was provided. 84 refs., 11 figs., 40 tabs.

The sedimentology, mineralogy and geochemistry of the Mooifontein deposit, Orange Free State

International Nuclear Information System (INIS)

Brynard, H.J.; Jakob, W.R.O.; Le Roux, J.P.

1982-08-01

The sedimentology, mineralogy and geochemistry of the Mooifontein deposit, which is situated north-west of Edenburg, Orange Free State, has been investigated. The orebody is located stratigraphically in the Adelaide Subgroup of the Karoo Sequence. Palaeocurrent and geological sections afford a picture of a fan-shaped distributary system and together with features such as small-scale channeling, cyclical deposition and an upward coarsening cycle, suggest a lacustrine-delta model of formation. The rocks constituting the deposit are feldspathic greywackes and feldspathic silt- and mudstones and can be divided into five texturally distinguishable groups. The mineralised lenses of the Mooifontein deposit attain a thickness of 7 m which can be split into two or three zones. The average grade of 0,85 kg U 3 O 8 /t is lower than that of the southern Karoo deposits (1 kg U 3 O 8 /t). The shallow depth of the orebody makes it amenable to open-cast mining. Molybdenum concentrations in the deposit are too low to be of economic significance. The sediments have low copper, vanadium and arsenic contents and the above-average calcite content of 9% will result in high acid consumption should an acid leaching process be used for uranium recovery. Both calcite and fluorite are unrelated to the uranium mineralisation. The deposit as a whole appears to have been little affected by post-genetic processes with only minor redistribution of uranium and moderate oxidation of organic carbon and sulphides

Assessment for Melting Temperature Measurement of Nucleic Acid by HRM.

Science.gov (United States)

Wang, Jing; Pan, Xiaoming; Liang, Xingguo

2016-01-01

High resolution melting (HRM), with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping. For the aim of extending HRM for the evaluation of thermal stability of nucleic acid secondary structures on sequence dependence, we investigated effects of the dye of EvaGreen, metal ions, and impurities (such as dNTPs) on melting temperature ( T m ) measurement by HRM. The accuracy of HRM was assessed as compared with UV melting method, and little difference between the two methods was found when the DNA T m was higher than 40°C. Both insufficiency and excessiveness of EvaGreen were found to give rise to a little bit higher T m , showing that the proportion of dye should be considered for precise T m measurement of nucleic acids. Finally, HRM method was also successfully used to measure T m s of DNA triplex, hairpin, and RNA duplex. In conclusion, HRM can be applied in the evaluation of thermal stability of nucleic acid (DNA or RNA) or secondary structural elements (even when dNTPs are present).

Ecosystem assessment methods for cumulative effects at the regional scale

International Nuclear Information System (INIS)

Hunsaker, C.T.

1989-01-01

Environmental issues such as nonpoint-source pollution, acid rain, reduced biodiversity, land use change, and climate change have widespread ecological impacts and require an integrated assessment approach. Since 1978, the implementing regulations for the National Environmental Policy Act (NEPA) have required assessment of potential cumulative environmental impacts. Current environmental issues have encouraged ecologists to improve their understanding of ecosystem process and function at several spatial scales. However, management activities usually occur at the local scale, and there is little consideration of the potential impacts to the environmental quality of a region. This paper proposes that regional ecological risk assessment provides a useful approach for assisting scientists in accomplishing the task of assessing cumulative impacts. Critical issues such as spatial heterogeneity, boundary definition, and data aggregation are discussed. Examples from an assessment of acidic deposition effects on fish in Adirondack lakes illustrate the importance of integrated data bases, associated modeling efforts, and boundary definition at the regional scale

Technology and economic assessment of lactic acid production and uses

Energy Technology Data Exchange (ETDEWEB)

Datta, R.; Tsai, S.P.

1996-03-01

Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}50,000 tons/yr) used in a wide range of food-processing and industrial applications. Potentially, it can become a very large-volume, commodity-chemical intermediate produced from carbohydrates for feedstocks of biodegradable polymers, oxygenated chemicals, environmentally friendly ``green`` solvents, and other intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from fermentation broths and its conversion to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. Development and deployment of novel separations technologies, such as electrodialysis with bipolar membranes, extractive and catalytic distillations, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The emerging technologies can use environmentally sound lactic acid processes to produce environmentally useful products, with attractive process economics. These technology advances and recent product and process commercialization strategies are reviewed and assessed.

Ahead of his time: Jacob Lipman's 1930 estimate of atmospheric sulfur deposition for the conterminous United States

Science.gov (United States)

Landa, Edward R.; Shanley, James B.

2015-01-01

A 1936 New Jersey Agricultural Experiment Station Bulletin provided an early quantitative assessment of atmospheric deposition of sulfur for the United States that has been compared in this study with more recent assessments. In the early 20th century, anthropogenic sulfur additions from the atmosphere to the soil by the combustion of fossil fuels were viewed as part of the requisite nutrient supply of crops. Jacob G. Lipman, the founding editor of Soil Science, and his team at Rutgers University, made an inventory of such additions to soils of the conterminous United States during the economic depression of the 1930s as part of a federally funded project looking at nutrient balances in soils. Lipman's team gathered data compiled by the US Bureau of Mines on coal and other fuel consumption by state and calculated the corresponding amounts of sulfur emitted. Their work pioneered a method of assessment that became the norm in the 1970s to 1980s—when acid rain emerged as a national issue. Lipman's estimate of atmospheric sulfur deposition in the 1930 is in reasonable agreement with recent historic reconstructions.

Relationships between indicators of acid-base chemistry and fish assemblages in streams of the Great Smoky Mountains National Park

Science.gov (United States)

Baldigo, Barry P.; Kulp, Matt A.; Schwartz, John S.

2018-01-01

The acidity of many streams in the Great Smoky Mountains National Park (GRSM) has increased significantly since pre-industrial (∼1850) times due to the effects of highly acidic atmospheric deposition in poorly buffered watersheds. Extensive stream-monitoring programs since 1993 have shown that fish and macroinvertebrate assemblages have been adversely affected in many streams across the GRSM. Matching chemistry and fishery information collected from 389 surveys performed at 52 stream sites over a 22-year period were assessed using logistic regression analysis to help inform the U.S. Environmental Protection Agency’s assessment of the environmental impacts of emissions of oxides of nitrogen (NOx) and sulfur (SOx). Numerous logistic equations and associated curves were derived that defined the relations between acid neutralizing capacity (ANC) or pH and different levels of community richness, density, and biomass; and density and biomass of brook trout, rainbow trout, and small prey (minnow) populations in streams of the GRSM. The equations and curves describe the status of fish assemblages in the GRSM under contemporary emission levels and deposition loads of nitrogen (N) and sulfur (S) and provide a means to estimate how newly proposed (and various alternative) target deposition loads, which strongly influence stream ANC, might affect key ecological indicators. Several examples using ANC, community richness, and brook trout density are presented to illustrate the steps needed to predict how future changes in stream chemistry (resulting from different target deposition loads of N and S) will affect the probabilities of observing specific levels of selected biological indicators in GRSM streams. The implications of this study to the regulation of NOx and SOx emissions, water quality, and fisheries management in streams of the GRSM are discussed, but also qualified by the fact that specific examples provided need to be further explored before recommendations

All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

Science.gov (United States)

Lausund, Kristian Blindheim; Nilsen, Ola

2016-11-01

Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

Wet deposition flux of trace elements to the Adirondack region

International Nuclear Information System (INIS)

Huang, X.; Keskin, S.S.; Gullu, G.; Olmez, I.

2001-01-01

Wet deposition samples from two locations in the Adirondack region of New York were analyzed for trace elemental composition by instrumental neutron activation analysis. Annual fluxes of the measured species were determined by precipitation-weighted and linear-regression methods. Despite several episodes of high deposition fluxes, the cumulative areal wet deposition of trace elements increased fairly linearly (r 2 > 0.9) over the two year sampling period at both sites. This implies that short duration sampling programs may be used to estimate long-term fluxes and cumulative wet deposition impacts. Based on the magnitude of their fluxes, the measured species have been divided into four groups: acidic anions, electroneutral balancing cations, and minor and trace elements of anthropogenic origin. (author)

The use of amino acid indices for assessing organic matter quality and microbial abundance in deep-sea Antarctic sediments of IODP Expedition 318

Science.gov (United States)

Carr, Stephanie A; Mills, Christopher T.; Mandernack, Kevin W

2016-01-01

The Adélie Basin, located offshore of the Wilkes Land margin, experiences unusually high sedimentation rates (~ 2 cm yr− 1) for the Antarctic coast. This study sought to compare depthwise changes in organic matter (OM) quantity and quality with changes in microbial biomass with depth at this high-deposition site and an offshore continental margin site. Sediments from both sites were collected during the International Ocean Drilling (IODP) Program Expedition 318. Viable microbial biomass was estimated from concentrations of bacterial-derived phospholipid fatty acids, while OM quality was assessed using four different amino acid degradation proxies. Concentrations of total hydrolysable amino acids (THAA) measured from the continental margin suggest an oligotrophic environment, with THAA concentrations representing only 2% of total organic carbon with relative proportions of non-protein amino acids β-alanine and γ-aminobutyric acid as high as 40%. In contrast, THAA concentrations from the near-shore Adélie Basin represent 40%–60% of total organic carbon. Concentrations of β-alanine and γ-aminobutyric acid were often below the detection limit and suggest that the OM of the basin as labile. DI values in surface sediments at the Adélie and margin sites were measured to be + 0.78 and − 0.76, reflecting labile and more recalcitrant OM, respectively. Greater DI values in deeper and more anoxic portions of both cores correlated positively with increased relative concentrations of phenylalanine plus tyrosine and may represent a change of redox conditions, rather than OM quality. This suggests that DI values calculated along chemical profiles should be interpreted with caution. THAA concentrations, the percentage of organic carbon (CAA%) and total nitrogen (NAA%) represented by amino acids at both sites demonstrated a significant positive correlation with bacterial abundance estimates. These data suggest that the selective degradation of amino acids, as

Deposit model for heavy-mineral sands in coastal environments: Chapter L in Mineral deposit models for resource assessment

Science.gov (United States)

Van Gosen, Bradley S.; Fey, David L.; Shah, Anjana K.; Verplanck, Philip L.; Hoefen, Todd M.

2014-01-01

This report provides a descriptive model of heavy-mineral sands, which are sedimentary deposits of dense minerals that accumulate with sand, silt, and clay in coastal environments, locally forming economic concentrations of the heavy minerals. This deposit type is the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, through recovery of the minerals ilmenite (Fe2+TiO3), rutile (TiO2), and leucoxene (an alteration product of ilmenite). Heavy-mineral sands are also the principal source of zircon (ZrSiO4) and its zirconium oxide; zircon is often recovered as a coproduct. Other heavy minerals produced as coproducts from some deposits are sillimanite/kyanite, staurolite, monazite, and garnet. Monazite [(Ce,La,Nd,Th)PO4] is a source of rare earth elements as well as thorium, which is used in thorium-based nuclear power under development in India and elsewhere.

Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode

International Nuclear Information System (INIS)

Selvaraju, T.; Ramaraj, R.

2007-01-01

The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 μM for AA and 20-50 μM for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results

Accounting of 131l decomposition under retrospective assessment of its deposition on the basis of determination of 129l deposition

Directory of Open Access Journals (Sweden)

Gavrilin Yu.l.

2013-12-01

given article aimed a justification of approaches to account of radioactive decay of 131l in the course of determination of its ground deposition density on the basis of determination of the ground deposition density of 129l at the late stage after the accident.

Post-deposition treatments of plasma-sprayed YBaCuO coatings deposited on nickel

Energy Technology Data Exchange (ETDEWEB)

Dube, D; Lambert, P; Arsenault, B; Champagne, B [National Research Council of Canada, Boucherville, PQ (Canada)

1990-12-15

As-sprayed YBaCuO coatings do not exhibit superconductivity because of the non-equilibrium solidification conditions of molten particles on the substrate and to the deposit's loss of oxygen. Therefore post-deposition treatments are required to restore the superconductivity. In this study, post-deposition treatments were carried out on thick YBaCuO coatings (200 {mu}m) deposited on cold nickel substrates to modify their microstructure, to restore the oxygen content and to improve their superconducting properties. These treatments consist in heating the coatings at various temperatures above 950deg C followed by controlled solidification cycles. The effect of these treatments on the microstructure of the coatings was assessed and the interaction between the coatings and the nickel substrate was also examined. Solidification cycles including a low cooling rate near the non-congruent melting temperature of YBa{sub 2}Cu{sub 3}O{sub x} and involving a temperature gradient were carried out to create a texture. (orig.).

Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Uicab, O. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Yazdani-Pedram, M. [Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, S. Livingstone 1007, Independencia, Santiago (Chile); Toro, P. [Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Beauchef 850, Santiago (Chile); Gamboa, F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico); Mazo, M.A.; Nistal, A.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain)

2016-11-01

Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO{sub 3}/H{sub 2}SO{sub 4} reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

Atmospheric deposition and canopy exchange processes in alpine forest ecosystems (northern Italy)

Energy Technology Data Exchange (ETDEWEB)

Balestrini, R. [Water Research Institute, Brugherio (Italy); Tagliaferri, A. [Regional Forestry Board (Italy)

2001-07-01

Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999) at two high elevation forest sites (Val Gerola and Val Masino) which were known to differ in terms of tree health, as assessed by live crown condition. The ion concentration of bulk precipitation samples did not differ significantly between sites, except for Mg{sup 2+}, while the throughfall concentrations differed in the measured values of H{sup +}, N-NO{sub 3}{sup -}, Cl{sup -}, Na{sup +}, K{sup +}, DOC and weak organic acids. The results of the application of the canopy exchange model indicated a higher contribution from the dry deposition of N-NO{sub 3}{sup -}, N-NH{sub 4}{sup +} and H{sup +} at Val Gerola, where the damage symptoms were more evident. In addition, the canopy leaching of Ca{sup 2+}, K{sup +} and weak organic acids were 47%, 21% and 27% higher at Val Gerola than at Val Masino. Annual SO{sub 4}{sup 2-} deposition fluxes (21.3kg ha{sup -1}yr{sup -1} at Val Masino and 23.6kgha{sup -1}yr{sup -1} at Val Gerola) were similar to those reported for moderately polluted European and U.S. sites. Annual N loads were 13.6 and 13.1kgha{sup -1}yr{sup -1} in the bulk input, and 15.0 and 18.0kgha{sup -1}yr{sup -1} in throughfall inputs, at Val Masino and Val Gerola, respectively. The contribution of the organic fraction to the total N atmospheric deposition load is significant, constituting 17% of the bulk flux and 40% of the throughfall flux. Measured nitrogen loads exceed the critical nutrient loads by several kgNha{sup -1} at both stations. In particular the nitrogen throughfall load at Val Gerola was about 3 times higher than the critical values. (author)

Mechanistic studies of formic acid oxidation at polycarbazole supported Pt nanoparticles

International Nuclear Information System (INIS)

Moghaddam, Reza B.; Pickup, Peter G.

2013-01-01

Highlights: •A polycarbazole support decreases the accumulation of adsorbed intermediates on Pt during formic acid oxidation. •Polycarbazole causes a bilayer of Cu to form on Pt nanoparticles during Cu underpotential deposition. •XPS suggests that both of these effects are due to electron donation from the metal (Pt or Cu) into the polymer π-system. -- Abstract: Mechanistic aspects of the promotion of formic acid oxidation at Pt nanoparticles supported on a thin layer of polycarbazole (PCZ) have been investigated by voltammetry and X-ray photoelectron spectroscopy (XPS). The Pt nanoparticles were drop coated onto a glassy carbon (GC) electrode coated with a ca. 9 nm layer of electrochemically deposited polycarbazole. After 500 s of formic acid oxidation at 0 V vs. SCE, the current at a GC/PCZ/Pt electrode was 25 times higher than at a GC/Pt electrode. Voltammetry in formic acid free H 2 SO 4 following potentiostatic oxidation of formic acid revealed that there was less accumulation of adsorbed intermediates for the polycarbazole supported Pt nanoparticles than for those deposited directly onto the glassy carbon with, 50% more Pt sites remaining available for the GC/PCZ/Pt electrode relative to the GC/Pt electrode. Independent CO stripping experiments revealed only slight differences, while Cu underpotential deposition surprisingly resulted in the deposition of a ca. two-fold excess of Cu on the polycarbazole supported particles. This observation was supported by XPS which also revealed a second Cu signal at a higher binding energy, suggesting electron donation into the conjugated π system of the polymer. Such an interaction of Pt with the polycarbazole may be responsible for its higher activity for formic acid oxidation

Characterization of a coal tailing deposit for zero waste mine in the Brazilian coal field of Santa Catarina

International Nuclear Information System (INIS)

Amaral Filho, J.R.; Schneider, I.A.H.; Tubino, R.M.C.; Brum de, I.A.S.; Miltzarek, G.; Sampaio, C.H.

2010-01-01

Coal tailings deposits in Brazil are occupying large areas of land while also generating acid mine drainage (AMD) that includes heavy metals. This paper described an analytical study of a typical coal tailings deposit. The study objective was to separate low density, intermediate density, and high density fractions for future reuse. Particle size analysis, disymmetric studies, X-ray diffraction, and tests conducted to determine ash, total sulphur, and acid bases were conducted in order to characterize the coal tailings samples. Results of the study demonstrated a size distribution of 67 percent coarse, 14 percent fine, and 19 percent ultra-fine particles. The gravimetric concentration method was used to recover 34.2 percent of the total deposit for future energy use. Approximately 9.2 percent of the remaining deposit was a pyrite concentrate. The acid generating potential of the remaining materials was reduced by approximately 60 percent. 9 refs., 1 tab., 2 figs.

Bulk deposition of base cationic nutrients in China's forests: Annual rates and spatial characteristics

Science.gov (United States)

Enzai Du; Wim de Vries; Steven McNulty; Mark E. Fenn

2018-01-01

Base cations, such as potassium (K+), calcium (Ca2+) and magnesium (Mg2+), are essential nutrients for plant growth and their atmospheric inputs can buffer the effect of acid deposition by nitrogen (N) and sulphur (S) compounds. However, the spatial variation in atmospheric deposition of these base...

Early infant adipose deposition is positively associated with the n-6 to n-3 fatty acid ratio in human milk independent of maternal BMI.

Science.gov (United States)

Rudolph, M C; Young, B E; Lemas, D J; Palmer, C E; Hernandez, T L; Barbour, L A; Friedman, J E; Krebs, N F; MacLean, P S

2017-04-01

Excessive infant weight gain in the first 6-month of life is a powerful predictor of childhood obesity and related health risks. In mice, omega-6 fatty acids (FAs) serve as potent ligands driving adipogenesis during early development. The ratio of omega-6 relative to omega-3 (n-6/n-3) FA in human milk (HM) has increased threefold over the last 30 years, but the impact of this shift on infant adipose development remains undetermined. This study investigated how maternal obesity and maternal dietary FA (as reflected in maternal red blood cells (RBCs) composition) influenced HM n-6 and n-3 FAs, and whether the HM n-6/n-3 ratio was associated with changes in infant adipose deposition between 2 weeks and 4 months postpartum. Forty-eight infants from normal weight (NW), overweight (OW) and obese (OB) mothers were exclusively or predominantly breastfed over the first 4 months of lactation. Mid-feed HM and maternal RBC were collected at either transitional (2 weeks) or established (4 months) lactation, along with infant body composition assessed using air-displacement plethysmography. The FA composition of HM and maternal RBC was measured quantitatively by lipid mass spectrometry. In transitional and established HM, docosahexaenoic acid (DHA) was lower (P=0.008; 0.005) and the arachidonic acid (AA)/DHA+eicosapentaenoic acid (EPA) ratio was higher (P=0.05; 0.02) in the OB relative to the NW group. Maternal prepregnancy body mass index (BMI) and AA/DHA+EPA ratios in transitional and established HM were moderately correlated (P=0.018; 0.001). Total infant fat mass was increased in the upper AA/DHA+EPA tertile of established HM relative to the lower tertile (P=0.019). The amount of changes in infant fat mass and percentage of body fat were predicted by AA/EPA+DHA ratios in established HM (P=0.038; 0.010). Perinatal infant exposures to a high AA/EPA+DHA ratio during the first 4 months of life, which is primarily reflective of maternal dietary FA, may significantly contribute to

50 CFR 270.16 - Deposit of funds.

Science.gov (United States)

2010-10-01

..., DEPARTMENT OF COMMERCE FISH AND SEAFOOD PROMOTION SPECIES-SPECIFIC SEAFOOD MARKETING COUNCILS § 270.16... approved marketing plan and budget, funds collected through assessments authorized by the Act must be deposited in any interest-bearing account or certificate of deposit of a bank that is a member of the...

Reactive nitrogen deposition to South East Asian rainforest

Science.gov (United States)

di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

2010-05-01

The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid

Integration of transcriptome and whole genomic resequencing data to identify key genes affecting swine fat deposition.

Directory of Open Access Journals (Sweden)

Kai Xing

Full Text Available Fat deposition is highly correlated with the growth, meat quality, reproductive performance and immunity of pigs. Fatty acid synthesis takes place mainly in the adipose tissue of pigs; therefore, in this study, a high-throughput massively parallel sequencing approach was used to generate adipose tissue transcriptomes from two groups of Songliao black pigs that had opposite backfat thickness phenotypes. The total number of paired-end reads produced for each sample was in the range of 39.29-49.36 millions. Approximately 188 genes were differentially expressed in adipose tissue and were enriched for metabolic processes, such as fatty acid biosynthesis, lipid synthesis, metabolism of fatty acids, etinol, caffeine and arachidonic acid and immunity. Additionally, many genetic variations were detected between the two groups through pooled whole-genome resequencing. Integration of transcriptome and whole-genome resequencing data revealed important genomic variations among the differentially expressed genes for fat deposition, for example, the lipogenic genes. Further studies are required to investigate the roles of candidate genes in fat deposition to improve pig breeding programs.

Assessment of undiscovered resources in calcrete uranium deposits, Southern High Plains region of Texas, New Mexico, and Oklahoma, 2017

Science.gov (United States)

Hall, Susan M.; Mihalasky, Mark J.; Van Gosen, Bradley S.

2017-11-14

The U.S. Geological Survey estimates a mean of 40 million pounds of in-place uranium oxide (U3O8) remaining as potential undiscovered resources in the Southern High Plains region of Texas, New Mexico, and Oklahoma. This estimate used a geology-based assessment method specific to calcrete uranium deposits.

Effect of Enhancers on in vitro and in vivo Skin Permeation and Deposition of S-Methyl-L-Methionine.

Science.gov (United States)

Kim, Ki Taek; Kim, Ji Su; Kim, Min-Hwan; Park, Ju-Hwan; Lee, Jae-Young; Lee, WooIn; Min, Kyung Kuk; Song, Min Gyu; Choi, Choon-Young; Kim, Won-Serk; Oh, Hee Kyung; Kim, Dae-Duk

2017-07-01

S-methyl- L -methionine (SMM), also known as vitamin U, is commercially available as skin care cosmetic products for its wound healing and photoprotective effects. However, the low skin permeation expected of SMM due to its hydrophilic nature with a log P value of -3.3, has not been thoroughly addressed. The purpose of this study thus was to evaluate the effect of skin permeation enhancers on the skin permeation/deposition of SMM. Among the enhancers tested for the in vitro skin permeation and deposition of SMM, oleic acid showed the most significant enhancing effect. Moreover, the combination of oleic acid and ethanol further enhanced in vitro permeation and deposition of SMM through hairless mouse skin. Furthermore, the combination of oleic acid and ethanol significantly increased the in vivo deposition of SMM in the epidermis/dermis for 12 hr, which was high enough to exert a therapeutic effect. Therefore, based on the in vitro and in vivo studies, the combination of oleic acid and ethanol was shown to be effective in improving the topical skin delivery of SMM, which may be applied in the cosmetic production process for SMM.

Impact of biomass burning on nutrient deposition to the global ocean

Science.gov (United States)

Kanakidou, Maria; Myriokefalitakis, Stelios; Daskalakis, Nikos; Mihalopoulos, Nikolaos; Nenes, Athanasios

2017-04-01

Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. These nutrients have also primary anthropogenic sources including combustion emissions. The global atmospheric N [1], Fe [2] and P [3] cycles have been parameterized in the global 3-D chemical transport model TM4-ECPL, accounting for inorganic and organic forms of these nutrients, for all natural and anthropogenic sources of these nutrients including biomass burning, as well as for the link between the soluble forms of Fe and P atmospheric deposition and atmospheric acidity. The impact of atmospheric acidity on nutrient solubility has been parameterised based on experimental findings and the model results have been evaluated by extensive comparison with available observations. In the present study we isolate the significant impact of biomass burning emissions on these nutrients deposition by comparing global simulations that consider or neglect biomass burning emissions. The investigated impact integrates changes in the emissions of the nutrients as well as in atmospheric oxidants and acidity and thus in atmospheric processing and secondary sources of these nutrients. The results are presented and thoroughly discussed. References [1] Kanakidou M, S. Myriokefalitakis, N. Daskalakis, G. Fanourgakis, A. Nenes, A. Baker, K. Tsigaridis, N. Mihalopoulos, Past, Present and Future Atmospheric Nitrogen Deposition, Journal of the Atmospheric Sciences (JAS-D-15

Simultaneous monitoring of biofilm growth, microbial activity, and inorganic deposits on surfaces with an in situ, online, real-time, non-destructive, optical sensor.

Science.gov (United States)

Strathmann, Martin; Mittenzwey, Klaus-Henrik; Sinn, Gert; Papadakis, Wassilios; Flemming, Hans-Curt

2013-01-01

Deposits on surfaces in water-bearing systems, also known as 'fouling', can lead to substantial losses in the performance of industrial processes as well as a decreased product quality. Early detection and localization of such deposits can, to a considerable extent, save such losses. However, most of the surfaces that become fouled, for example, in process water pipes, membrane systems, power plants, and food and beverage industries, are difficult to access and analyses conducted on the water phase do not reveal the site or extent of deposits. Furthermore, it is of interest to distinguish biological from non-biological deposits. Although they usually occur together, different countermeasures are necessary. Therefore, sensors are required that indicate the development of surface fouling in real-time, non-destructively, and in situ, preferably allowing for discrimination between chemical and/or biological deposits. In this paper, an optical deposit sensor is presented which fulfills these requirements. Based on multiple fluorescence excitation emission matrix analysis, it detects autofluorescence of amino acids as indicators of biomass. Autofluorescence of nicotinamide adenine dinucleotide + hydrogen is interpreted as an indicator of biological activity, thus it acts as a viability marker, making the method suited for assessing the efficacy of disinfection treatments. Scattering signals from abiotic deposits such as calcium carbonate or corrosion products can clearly be distinguished from biotic substances and monitored separately. The sensor provides an early warning of fouling, allowing for timely countermeasures to be deployed. It also provides an assessment of the success of cleaning treatments and is a promising tool for integrated antifouling strategies.

Reduced European emissions of S and N - Effects on air concentrations, deposition and soil water chemistry in Swedish forests

Energy Technology Data Exchange (ETDEWEB)

Pihl Karlsson, Gunilla, E-mail: gunilla.pihl.karlsson@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden); Akselsson, Cecilia, E-mail: cecilia.akselsson@nateko.lu.se [Department of Earth and Ecosystem Sciences, Lund University, Soelvegatan 12, SE-223 62 Lund (Sweden); Hellsten, Sofie, E-mail: sofie.hellsten@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden); Karlsson, Per Erik, E-mail: pererik.karlsson@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden)

2011-12-15

Changes in sulphur and nitrogen pollution in Swedish forests have been assessed in relation to European emission reductions, based on measurements in the Swedish Throughfall Monitoring Network. Measurements were analysed over 20 years with a focus on the 12-year period 1996 to 2008. Air concentrations of SO{sub 2} and NO{sub 2}, have decreased. The SO{sub 4}-deposition has decreased in parallel with the European emission reductions. Soil water SO{sub 4}-concentrations have decreased at most sites but the pH, ANC and inorganic Al-concentrations indicated acidification recovery only at some of the sites. No changes in the bulk deposition of inorganic nitrogen could be demonstrated. Elevated NO{sub 3}-concentrations in the soil water occurred at irregular occasions at some southern sites. Despite considerable air pollution emission reductions in Europe, acidification recovery in Swedish forests soils is slow. Nitrogen deposition to Swedish forests continues at elevated levels that may lead to leaching of nitrate to surface waters. - Highlights: > S deposition to Swedish forests has decreased in parallel with European emissions. > Soil water pH, ANC and inorganic Al-concentrations indicated a slow recovery. > The bulk deposition of inorganic nitrogen over Sweden has not decreased. > Continued N deposition to Swedish forests may cause leaching of N to surface waters. - Reduced European emissions have led to decreased acidic deposition and a slow recovery of soil water but nitrogen deposition remains the same in Swedish forests.

Transient inhibition of connective tissue infiltration and collagen deposition into porous poly(lactic-co-glycolic acid) discs.

Science.gov (United States)

Love, Ryan J; Jones, Kim S

2013-12-01

Connective tissue rapidly proliferates on and around biomaterials implanted in vivo, which impairs the function of the engineered tissues, biosensors, and devices. Glucocorticoids can be utilized to suppress tissue ingrowth, but can only be used for a limited time because they nonselectively arrest cell proliferation in the local environment. The present study examined use of a prolyl-4-hydroxylase inhibitor, 1,4-dihydrophenonthrolin-4-one-3-carboxylic acid (1,4-DPCA), to suppress connective tissue ingrowth in porous PLGA discs implanted in the peritoneal cavity for 28 days. The prolyl-4-hydroxylase inhibitor was found to be effective at inhibiting collagen deposition within and on the outer surface of the disc, and also limited connective tissue ingrowth, but not to the extent of glucocorticoid inhibition. Finally, it was discovered that 1,4-DPCA suppressed Scavenger Receptor A expression on a macrophage-like cell culture, which may account for the drug's ability to limit connective tissue ingrowth in vivo. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

Forest canopy uptake of atmospheric nitrogen deposition at eastern U.S. conifer sites: Carbon storage implications?

Science.gov (United States)

Herman Sievering; Ivan Fernandez; John Lee; John Hom; Lindsey Rustad

2000-01-01

Dry deposition determinations, along with wet deposition and throughfall (TF) measurements, at a spruce fir forest in central Maine were used to estimate the effect of atmospherically deposited nitrogen (N) uptake on forest carbon storage. Using nitric acid and particulate N as well as TF ammonium and nitrate data, the growing season (May-October) net canopy uptake of...

Probing the application of Fourier Transform Infrared (FTIR) spectroscopy for assessment of deposited flux of Radon and Thoron progeny in high exposure conditions

Energy Technology Data Exchange (ETDEWEB)

Mishra, R., E-mail: rosaline@barc.gov.in; Sapra, B.K.; Rout, R.P.; Prajith, R.

2016-12-01

Direct measurement of Radon and Thoron progeny in the atmosphere and occupational environments such as Uranium mines, Uranium and Thorium handling facilities has gained importance because of its radiological significance in inhalation dose assessment. In this regard, Radon and Thoron Progeny sensors (DTPS and DRPS) are the only passive solid state nuclear track detector (SSNTD, LR115) based devices which are being extensively used for time integrated direct progeny measurements. An essential component of the analysis is the chemical etching of the detectors, followed by spark counting of tracks and then estimation of the inhalation dose using appropriate calibration factors. Alternatively, the tracks may be counted using image analysis techniques. However, under high exposure conditions, both these methods have inherent limitations and errors arising due to increased frequency of tracks. In the present work, we probe the use of Fourier Transform Infra Red (FTIR) spectroscopy to analyse the deposited fluence of the progeny particulates based on change in transmittance of the nitric group vibrational bands of the LR115. A linear relationship between the transmittance and the deposited fluence was observed, which can be used to estimate the deposited fluence rate and the inhalation dose. This alternative method of analysis will provide a faster and non-destructive technique for inhalation dose assessment, specially for routine large scale measurements. - Highlights: • An alternative method of inhalation dose assessment. • Linearity between the transmittance of nitric goup bands and the deposited fluence. • Faster and non-destructive technique for high exposure scenarios.

Acidic deposition: State of science and technology. Report 15. Liming acidic surface waters. Final report

International Nuclear Information System (INIS)

Olem, H.; Thornelof, E.; Sandoy, S.; Schreiber, R.K.

1990-09-01

The document describes the science and technology of aquatic liming--a method for improving the water quality of acidic surface waters to restore or enhance fisheries. The report is a comprehensive compilation of years of research in North America and Europe by dozens of scientists. Several mitigation technologies--including those that have only been proposed--are critically evaluated along with the effects of liming on water chemistry and aquatic biota. Through these evaluations, the state of the science and technology of aquatic liming is identified for the reader. Whole-lake liming is now recognized as a valuable management tool for acidic surface waters and their fisheries. However, some liming technologies are considered experimental and will need further evaluation. Distinctions between technologies are included--as is the distinction between liming acidic surface waters and reducing acidifying emissions

SEM and XPS study of layer-by-layer deposited polypyrrole thin films

Science.gov (United States)

Pigois-Landureau, E.; Nicolau, Y. F.; Delamar, M.

1996-01-01

Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3-4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces.

Compound depositions from the BOPEC fires on Bonaire : Measurements and risk assessment

NARCIS (Netherlands)

van de Meent D; Bodar CWM; Boshuis ME; de Groot AC; de Zwart D; Hoffer SM; Janssen PJCM; Mooij M; de Groot GM; Peijnenburg WJGM; Verbruggen EMJ; IMG; SEC; LER; mev

2011-01-01

Some polycyclic aromatic hydrocarbons (PAHs) and some perfluorinated fire fighting foam constituents (especially perfluorooctane sulfonate, PFOS) were found in deposited soot and in water on Bonaire due to the BOPEC oil depot fires in September 2010. The soot deposition did not result in elevated

Assessment of antitumoral and antimicrobial effects of a maslinic acid derivative

Directory of Open Access Journals (Sweden)

Ioana Z. Pavel

2016-12-01

Full Text Available INTRODUCTION Maslinic acid, a naturally occurring triterpene, has been reported to possess several therapeutic effects including antioxidant, anti-inflammatory and antiparasitic properties. Structural changes of the compound led to the development of new derivatives in order to expand the spectrum of activities. OBJECTIVES AND BACKGROUND The present study was purposed to assess the in vitro antitumoral and antibacterial effects of a maslinic acid derivative, namely benzyl (2α, 3β 2,3-diacetoxy-olean-12- en-28-amide (EM2. MATERIALS AND METHODS Four compound concentrations (12.5, 25, 50 and 100 µM were evaluated for their cytotoxic effect on A375 human melanoma and B164A5 murine melanoma cell lines using the MTT assay. Furthermore, EM2 was tested on ten bacterial strains by means of agar disk diffusion method with the assessment of the inhibition zone diameters at 24h period of time. RESULTS EM2 elicited a dose-dependent cytotoxic effect on both melanoma cell lines. Regarding the antibacterial activity, EM2 determined a significant growth inhibition on Streptococcus pyogenes (20 ± 0.26 mm and Staphylococcus aureus (13 ± 0.19 mm. CONCLUSIONS The tested maslinic acid derivative is a promising antitumoral agent against skin cancer and antimicrobial agent against cocci bacteria. Graphical abstract: EM2 in vitro effects

Aerosol Deposition in Health and Disease

Science.gov (United States)

2012-01-01

Abstract The success of inhalation therapy is not only dependent upon the pharmacology of the drugs being inhaled but also upon the site and extent of deposition in the respiratory tract. This article reviews the main mechanisms affecting the transport and deposition of inhaled aerosol in the human lung. Aerosol deposition in both the healthy and diseased lung is described mainly based on the results of human studies using nonimaging techniques. This is followed by a discussion of the effect of flow regime on aerosol deposition. Finally, the link between therapeutic effects of inhaled drugs and their deposition pattern is briefly addressed. Data show that total lung deposition is a poor predictor of clinical outcome, and that regional deposition needs to be assessed to predict therapeutic effectiveness. Indeed, spatial distribution of deposited particles and, as a consequence, drug efficiency is strongly affected by particle size. Large particles (>6 μm) tend to mainly deposit in the upper airway, limiting the amount of drugs that can be delivered to the lung. Small particles (<2 μm) deposit mainly in the alveolar region and are probably the most apt to act systemically, whereas the particle in the size range 2–6 μm are be best suited to treat the central and small airways. PMID:22686623

Deposition of aqueous aerosol of technetium-99m diethylene triamine penta-acetic acid generated and delivered by a novel system (AERx) in healthy subjects

International Nuclear Information System (INIS)

Chan, H.K.; Eberl, S.; Bautovich, G.

1999-01-01

Deposition of technetium-99m diethylene triamine penta-acetic acid aqueous radioaerosols generated by a novel aerosol delivery system (AER x ) was studied in six healthy subjects using both planar and single-photon emission tomography (SPET) imaging. AER x is a microprocessor-controlled, bolus inhalation device that is actuated at pre-programmed values of inspiratory flow rate and volume. The aims of the study were to determine the effects of posture and inhaled volume upon deposition of the aerosol in the lungs. Each subject inhaled the radioaerosol in two positions (supine vs sitting) and with two inspiratory manoeuvres [vital capacity (VC) vs ''fixed volume'' of 1 l above functional residual capacity]. Simultaneous transmission-emission planar and tomographic images were acquired. The results showed diffuse deposition of the aerosol in the lung. Neither the breathing manoeuvre nor the posture was found to affect the distribution of the aerosol as measured by the ratio of the activity (counts per pixel) in the peripheral:central (penetration index, PI) or in the apex:base regions of the planar lung images (P>0.1). A small, albeit statistically significant, difference in PI (P x system showed high efficiency of delivery, with approximately 50% of the extruded dose in the device depositing in the lung. The uniformity of radioactivity distributed throughout the lung is attributed to the fine particle size (mass median aerodynamic diameter of 2 μm) of the aerosol and the electronic control of aerosol inhalation by the device. In conclusion, the AER x system can be ideal for diffuse aerosol deposition of therapeutic or diagnostic agents and is largely unaffected by inhaled volume and posture. The efficiency of the device device can limit the total radiation exposure of patients and staff administering the radioaerosols, and can make it suitable for delivery of expensive drugs. (orig.)

Increased Arctic Deposition of Persistent Compounds as a Result of the Montreal Protocol

Science.gov (United States)

Young, C.; Pickard, H. M.; De Silva, A. O.; Spencer, C.; Criscitiello, A. S.; Muir, D.; Sharp, M. J.

2017-12-01

Perfluorocarboxylic acids (PFCAs) are among the diverse groups of compounds characterized as persistent organic pollutants. They are toxic, resistant to environmental degradation, and adversely impact human and environmental health. PFCAs with four or fewer carbons, short-chain PFCAs (scPFCAs), are of particular interest because of their increasing levels in the environment, toxicity to plants, and potential for accumulation in some aquatic ecosystems, making them an emerging environmental concern. A minor source of scPFCAs to the Arctic has been shown to be atmospheric transformation of fluoropolymer precursors, followed by deposition. Additional potential sources of scPFCAs to the Arctic are chlorofluorocarbon (CFC)-replacement compounds. Through analysis of an ice core from the Canadian High Arctic, we show that Montreal Protocol-mandated introduction of CFC-replacement compounds for the heat-transfer industry has led to increasing inputs of these scPFCAs to the remote environment. Flux measurements for scPFCAs as a class of contaminants have only been reported in a couple studies to date. Here, we provide the first multi-decadal temporal record of scPFCA deposition, demonstrating a dramatic increase in deposition resulting from emission of CFC-replacements. These results bring to the forefront a need for a holistic approach to environmental risk assessment that considers impacts of replacement substances and degradation products.

Novel texturing method for sputtered zinc oxide films prepared at high deposition rate from ceramic tube targets

Directory of Open Access Journals (Sweden)

Hüpkes J.

2011-10-01

Full Text Available Sputtered and wet-chemically texture etched zinc oxide (ZnO films on glass substrates are regularly applied as transparent front contact in silicon based thin film solar cells. In this study, chemical wet etching in diluted hydrofluoric acid (HF and subsequently in diluted hydrochloric acid (HCl on aluminum doped zinc oxide (ZnO:Al films deposited by magnetron sputtering from ceramic tube targets at high discharge power (~10 kW/m target length is investigated. Films with thickness of around 800 nm were etched in diluted HCl acid and HF acid to achieve rough surface textures. It is found that the etching of the films in both etchants leads to different surface textures. A two steps etching process, which is especially favorable for films prepared at high deposition rate, was systematically studied. By etching first in diluted hydrofluoric acid (HF and subsequently in diluted hydrochloric acid (HCl these films are furnished with a surface texture which is characterized by craters with typical diameter of around 500 − 1000 nm. The resulting surface structure is comparable to etched films sputtered at low deposition rate, which had been demonstrated to be able to achieve high efficiencies in silicon thin film solar cells.

Quantitative measurement of aerosol deposition on skin, hair and clothing for dosimetric assessment